{"id":61,"date":"2025-09-05T02:33:53","date_gmt":"2025-09-05T02:33:53","guid":{"rendered":"https:\/\/support.nullflag.com\/?post_type=docs&#038;p=61"},"modified":"2025-10-30T13:34:29","modified_gmt":"2025-10-30T13:34:29","password":"","slug":"java-basic-syntax","status":"publish","type":"docs","link":"https:\/\/www.nullflag.com\/support\/kb\/cpp_c_java_arm64_javascript\/java_basic\/java-basic-syntax\/","title":{"rendered":"Java Basic Syntax"},"content":{"rendered":"\n<h2 class=\"wp-block-heading\">Basic Syntax<\/h2>\n\n\n\n<p>Initial Code Analysis: hello.java<\/p>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-9d8701ff\"\n     id=\"betterdocs-code-snippet-9d8701ff\"\n     data-language=\"java\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\u2615<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">java<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-9d8701ff .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-java\"><code>public class Hello {\n    public static void main(String[] args) {\n        System.out.println(&quot;Hello  There~&quot;);\n    }\n}<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-9d8701ff');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<p>Main function &amp; the entry point of the program.<\/p>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-183a13db\"\n     id=\"betterdocs-code-snippet-183a13db\"\n     data-language=\"java\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\u2615<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">java<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-183a13db .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-java\"><code>def func():\n    pass\n\nif __name__ == &quot;__main__&quot;:\n\tfunc()<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-183a13db');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<p>FileName<\/p>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-a8ce81ac\"\n     id=\"betterdocs-code-snippet-a8ce81ac\"\n     data-language=\"javascript\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\ud83d\udcc4<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">description<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-a8ce81ac .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-javascript\"><code>A file can contain at most one public class, and the file name must be the same as the public class name.\nIf the file contains multiple classes, the file name must still match the public class name.\nIf the file contains multiple classes but no public class, the file name can be any class name.<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-a8ce81ac');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<p>Class Naming<\/p>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-a2e3ab11\"\n     id=\"betterdocs-code-snippet-a2e3ab11\"\n     data-language=\"java\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\u2615<\/span>\n                                            <\/div>\n                \n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-a2e3ab11 .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-java\"><code>Use PascalCase with the first letter capitalized, e.g.\uff1aHello\u3001UserInfo\u3001PersonApplication<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-a2e3ab11');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<p>Class modifiers: public, default (if omitted).<br>Member modifiers inside classes: public, private, protected, default (if omitted).<br>Static members can be called directly without instantiation.<\/p>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-84424d94\"\n     id=\"betterdocs-code-snippet-84424d94\"\n     data-language=\"java\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\u2615<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">java<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-84424d94 .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-java\"><code>class MyTest{\n\n    public void f1(){\n        System.out.println(&quot;f1&quot;);\n    }\n\n    public static void f2(){\n        System.out.println(&quot;f2&quot;);\n    }\n}\n\npublic class Hello {\n\n    public static void main(String[] args) {\n        MyTest.f2();\n        \n        \/\/1.Instantiate\n        MyTest obj = new MyTest();\n        \/\/ 2.Object call\n        obj.f1();\n\n    }\n}<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-84424d94');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-0ce35df3\"\n     id=\"betterdocs-code-snippet-0ce35df3\"\n     data-language=\"java\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\u2615<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">java<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-0ce35df3 .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-java\"><code>\/**\n * @author calleng\n * @version 1.0\n * @date 2024\/07\/04 14:58\n * @desc\n *\/\n\nclass Person{\n    public static void showInfo() {\n        System.out.println(&quot;ningkong detail information&quot;);\n    }\n\n    public void doSomething(){\n        \/\/ Instance method\n        System.out.println(&quot;Instance method&quot;);\n    }\n}\n\npublic class Main {\n    public static void main(String[] args) {\n        Person.showInfo();  \/\/ 1. Static function direct call\n          \/\/1.Instantiate\n        Person obj = new Person();    \/\/ Instantiate object obj = new Person();\n         \/\/ 2.2. Object call\n        obj.doSomething();   \/\/ Object calls doSomething\n    }\n}<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-0ce35df3');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-e2bec565\"\n     id=\"betterdocs-code-snippet-e2bec565\"\n     data-language=\"javascript\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\ud83d\udcc4<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">java<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-e2bec565 .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-javascript\"><code>class Person {\n    public void f2() {\n        \/\/  Instance method\n        System.out.println(&quot;I am the F1 function&quot;);\n    }\n}\n\npublic class Hello {\n    public static void main(String[] args) {\n        \/\/  Instantiate object  obj = new Person();\n        Person obj = new Person();\n\n        \/\/ Object calls f2\n        obj.f2();\n    }\n}<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-e2bec565');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<p>void indicates that a method does not return a value.<br>If a method does return a value, you must specify the return type in the method definition.<br>Method names should use camelCase naming convention.<\/p>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-c8806517\"\n     id=\"betterdocs-code-snippet-c8806517\"\n     data-language=\"java\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\u2615<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">java<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-c8806517 .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-java\"><code>class MyTest{\n\n    public int f1(){  \/\/  If there is a return value, the method definition must specify the return type.\n        System.out.println(&quot;f1&quot;);\n\n        return 123;\n    }\n\n    public static String f2(){\n        System.out.println(&quot;f2&quot;);\n        return &quot;hahaha&quot;;\n    }\n}\n\npublic class Main {\n\n    public static void main(String[] args) {\n\n        MyTest obj = new MyTest();  \/\/ Instantiate object obj = new MyTest()\n        int v1 = obj.f1();\n\n        String v2 = MyTest.f2();\n    }\n}\n<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-c8806517');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<p>Parameters<br>Parameters must explicitly indicate what type they are.<\/p>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-11770617\"\n     id=\"betterdocs-code-snippet-11770617\"\n     data-language=\"java\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\u2615<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">java<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-11770617 .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-java\"><code>class MyTest {\n\n    public int f1(int a1, int a2) {  \/\/ Parameters must explicitly specify their type.\n        int result = a1 + a2;\n        return result;\n    }\n\n}\n\npublic class Main {\n\n    public static void main(String[] args) { \/\/  main\u2019s parameter type \u2192 String array, which is a container holding strings.\n        MyTest obj = new MyTest();\n        int v1 = obj.f1(1, 2);\n    }\n}<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-11770617');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<p>Supplement<\/p>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-372d1f32\"\n     id=\"betterdocs-code-snippet-372d1f32\"\n     data-language=\"java\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\u2615<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">java<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-372d1f32 .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-java\"><code>Doesn\u2019t the official Python source code also have definitions similar to Java?\n\ndef func(a1,a2):\n\treturn a1 + a2\n\n# Suggestion\ndef foo(a1: str a2:int) -&gt; int\n\treturn 1\n\nfoo(11,22)<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-372d1f32');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<h2 class=\"wp-block-heading\">Comments<\/h2>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-a114ba96\"\n     id=\"betterdocs-code-snippet-a114ba96\"\n     data-language=\"java\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\u2615<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">java<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-a114ba96 .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-java\"><code>\/**\n * Comment for this class\n *\/\npublic class Hello {\n\n    \/**\n     * What does this method do ...\n     * @param v1 size\n     * @param v2 dimension\n     * @return returns some value (xxx)\n     *\/\n    public static String getSign(int v1, String v2) {\n        return &quot;This is very hapy&quot;;\n    }\n\n    public static void main(String[] args) {\n        \/\/ Single-line comment # \n        \/\/ int age = 18;\n\n        \/* Multi-line comment \n        String name = &quot;Calleng&quot;;\n        int size = 18;\n         *\/\n    }\n}<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-a114ba96');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<h2 class=\"wp-block-heading\">Variables and Constants<\/h2>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-dd1aab05\"\n     id=\"betterdocs-code-snippet-dd1aab05\"\n     data-language=\"java\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\u2615<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">java<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-dd1aab05 .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-java\"><code>public class Hello {\n\n    public static void main(String[] args) {\n        String name = &quot;Ning kong &quot;;\n        name = &quot;calleng&quot;;\n\n        int age = 19;   \/\/Define variable\n        age = 20;     \/\/ Can be modified later \n\n        final int size = 18;  \/\/Define constant, fixed value\n    }\n}<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-dd1aab05');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<p>Output<\/p>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-c8ac3638\"\n     id=\"betterdocs-code-snippet-c8ac3638\"\n     data-language=\"java\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\u2615<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">filename.js<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-c8ac3638 .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-java\"><code>v1 = [111,22]\nv2 = 345<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-c8ac3638');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<h2 class=\"wp-block-heading\">Input and Output<\/h2>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-2f738df3\"\n     id=\"betterdocs-code-snippet-2f738df3\"\n     data-language=\"java\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\u2615<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">java<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-2f738df3 .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-java\"><code>import java.util.Scanner;\n\npublic class Hello {\n\n    public static void main(String[] args) {\n        \/\/ Input\n        Scanner input = new Scanner(System.in);\n        String text = input.nextLine();\n\n        \/\/ Output\n        System.out.println(text);  \/\/ println means it will print with a new line\n        \/\/ System.out.print(text);\n    }\n}<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-2f738df3');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-c71b2862\"\n     id=\"betterdocs-code-snippet-c71b2862\"\n     data-language=\"java\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\u2615<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">java<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-c71b2862 .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-java\"><code>import java.util.Scanner;\n\npublic class Hello {\n\n    public static void main(String[] args) {\n        \/\/ output\n        System.out.print(&quot;Please Input the words\uff1a&quot;);\n\n        \/\/ Input\n        Scanner input = new Scanner(System.in);\n        String text = input.nextLine();\n\n        \/\/ output\n        System.out.println(text);\n    }\n}<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-c71b2862');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<h2 class=\"wp-block-heading\">conditional statement<\/h2>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-41dd7368\"\n     id=\"betterdocs-code-snippet-41dd7368\"\n     data-language=\"java\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\u2615<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">if&#8230;else if&#8230;else<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-41dd7368 .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-java\"><code>public class Hello {\n\n    public static void main(String[] args) {\n        int age = 19;\n\n        if (age &lt; 18) {\n            System.out.println(&quot;Teenager&quot;);\n        } else if (age &lt; 40) {\n            System.out.println(&quot;Adult&quot;);\n        } else {\n            System.out.println(&quot;Senior&quot;);\n        }\n    }\n}\n<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-41dd7368');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-2ad0c6c2\"\n     id=\"betterdocs-code-snippet-2ad0c6c2\"\n     data-language=\"java\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\u2615<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">switch<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-2ad0c6c2 .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-java\"><code>public class Hello {\n\n    public static void main(String[] args) {  \/\/ Conditional branching with switch\n        int score = 85;\n\n        switch (score \/ 10) {   \/\/ Divide by 10 to group ranges (80\u201389, 90\u201399, etc.)\n            case 10:\n            case 9:\n                System.out.println(&quot;Grade: A&quot;);\n                break;\n            case 8:\n                System.out.println(&quot;Grade: B&quot;);\n                break;\n            case 7:\n                System.out.println(&quot;Grade: C&quot;);\n                break;\n            case 6:\n                System.out.println(&quot;Grade: D&quot;);\n                break;\n            default:\n                System.out.println(&quot;Grade: F&quot;);\n                break;\n        }\n    }\n}\n<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-2ad0c6c2');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<h2 class=\"wp-block-heading\">Loop Statements<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">while loop<\/h3>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-2i9q51k\"\n     id=\"betterdocs-code-snippet-2i9q51k\"\n     data-language=\"java\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\u2615<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">Runs while the condition is true.<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-2i9q51k .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-java\"><code>public class Hello {\n    public static void main(String[] args) {\n        int count = 0;\n        while (count &lt; 3) {\n            System.out.println(&quot;Processing...&quot;);\n            count += 1; \/\/ increment to avoid infinite loop\n        }\n    }\n}\n<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-2i9q51k');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-a609d50a\"\n     id=\"betterdocs-code-snippet-a609d50a\"\n     data-language=\"java\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\u2615<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">A slightly richer example (countdown):<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-a609d50a .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-java\"><code>public class Hello {\n    public static void main(String[] args) {\n        int seconds = 3;\n        while (seconds &gt; 0) {\n            System.out.println(&quot;Countdown: &quot; + seconds);\n            seconds--;\n        }\n        System.out.println(&quot;Go!&quot;);\n    }\n}\n<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-a609d50a');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<h3 class=\"wp-block-heading\">do\u2026while loop (executes at least once)<\/h3>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-e7ed492f\"\n     id=\"betterdocs-code-snippet-e7ed492f\"\n     data-language=\"java\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\u2615<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">Condition is checked after the body.<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-e7ed492f .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-java\"><code>public class Hello {\n    public static void main(String[] args) {\n        int count = 0;\n        do {\n            System.out.println(&quot;Processing...&quot;);\n            count += 1;\n        } while (count &lt; 3);\n    }\n}\n<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-e7ed492f');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<h3 class=\"wp-block-heading\">for loop<\/h3>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-897aca65\"\n     id=\"betterdocs-code-snippet-897aca65\"\n     data-language=\"java\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\u2615<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">Classic counter-based loop.<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-897aca65 .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-java\"><code>public class Hello {\n    public static void main(String[] args) {\n        for (int i = 0; i &lt; 10; i++) {\n            System.out.println(&quot;Hello&quot;);\n        }\n    }\n}\n<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-897aca65');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-9fc1e1fc\"\n     id=\"betterdocs-code-snippet-9fc1e1fc\"\n     data-language=\"java\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\u2615<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">Looping over arrays: index-based<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-9fc1e1fc .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-java\"><code>public class Hello {\n\n    public static void main(String[] args) {\n         String[] names = {&quot;Alice&quot;, &quot;Bob&quot;, &quot;Child&quot;, &quot;BaiDen&quot;};\n        \/\/ nameList.length   4\n        \/\/ nameList[0]\n\n        for (int idx = 0; idx &lt; nameList.length; idx++) {\n            String ele = nameList[idx];\n            System.out.println(&quot;Index &quot; + i + &quot; -&gt; &quot; + item);\n        }\n    }\n}<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-9fc1e1fc');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-67880f66\"\n     id=\"betterdocs-code-snippet-67880f66\"\n     data-language=\"java\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\u2615<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">Attention\uff1abreak and continue Both are supported in loops.<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-67880f66 .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-java\"><code>public class Hello {\n    public static void main(String[] args) {\n        \/\/ break: exit the loop immediately\n        for (int i = 1; i &lt;= 10; i++) {\n            if (i == 5) break; \/\/ stop at 5\n            System.out.print(i + &quot; &quot;); \/\/ 1 2 3 4\n        }\n        System.out.println();\n\n        \/\/ continue: skip the current iteration\n        for (int i = 1; i &lt;= 10; i++) {\n            if (i % 2 == 0) continue; \/\/ skip evens\n            System.out.print(i + &quot; &quot;); \/\/ 1 3 5 7 9\n        }\n        System.out.println();\n    }\n}\n<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-67880f66');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<p><\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Data Types<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">int type<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li>byte \u2014 1 byte. Range: -128 ~ 127 (i.e., -2^7 ~ 2^7 &#8211; 1)<\/li>\n\n\n\n<li>short \u2014 2 bytes. Range: -32,768 ~ 32,767<\/li>\n\n\n\n<li>int \u2014 4 bytes. Range: -2,147,483,648 ~ 2,147,483,647<\/li>\n\n\n\n<li>long \u2014 8 bytes. Range: -9,223,372,036,854,775,808 ~ 9,223,372,036,854,775,807<\/li>\n<\/ul>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-266fff2a\"\n     id=\"betterdocs-code-snippet-266fff2a\"\n     data-language=\"java\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\u2615<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">java<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-266fff2a .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-java\"><code>public class Hello {\n    public static void main(String[] args) {\n        byte  v1 = 32;\n        short v2 = 10_000;\n        int   v3 = 22_221_331;\n        long  v4 = 554_534_353_424L; \/\/ note the L suffix for long literals\n    }\n}\n<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-266fff2a');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<p>Reminder (RE context) In reverse engineering, some strings are stored\/handled as byte arrays (often UTF-8).<\/p>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-e2d81a13\"\n     id=\"betterdocs-code-snippet-e2d81a13\"\n     data-language=\"java\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\u2615<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">filename.js<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-e2d81a13 .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-java\"><code>name = &quot;Ningkong&quot;                    # Define a string containing Chinese characters\nvalue = name.encode(&quot;utf-8&quot;)        # Encode to UTF-8 bytes\nprint(value)                        # b&#039;\\xe9\\xb2\\x9c\\xe5\\xae\\x81&#039;\ninfo = [b for b in value]           # Store each byte (0\u2013255) in a list\nprint(info)                         # [233, 178, 156, 229, 174, 129]\n<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-e2d81a13');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-588fa0b2\"\n     id=\"betterdocs-code-snippet-588fa0b2\"\n     data-language=\"java\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\u2615<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">Java: bytes \u2194 strings (encoding)<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-588fa0b2 .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-java\"><code>import java.nio.charset.Charset;\nimport java.nio.charset.StandardCharsets;\nimport java.util.Arrays;\n\npublic class Hello {\n    public static void main(String[] args) {\n        \/\/ 1) Byte array \u2192 String (these are ASCII codes; result is a URL-like query string)\n        byte[] data = {\n            97,105,100,61,50,52,54,51,56,55,53,55,49,38,97,117,116,111,95,112,108,97,121,61,48,38,\n            99,105,100,61,50,56,57,48,48,56,52,52,49,38,100,105,100,61,75,82,69,104,69,83,77,85,\n            74,104,56,116,70,67,69,86,97,82,86,112,69,50,116,97,80,81,107,55,87,67,104,67,74,103,\n            38,101,112,105,100,61,48,38,102,116,105,109,101,61,49,54,50,55,49,48,48,57,51,55,38,\n            108,118,61,48,38,109,105,100,61,48,38,112,97,114,116,61,49,38,115,105,100,61,48,38,\n            115,116,105,109,101,61,49,54,50,55,49,48,52,51,55,50,38,115,117,98,95,116,121,112,101,\n            61,48,38,116,121,112,101,61,51\n        };\n\n        \/\/ Specify charset explicitly (UTF-8 here is fine for ASCII subset too)\n        String dataString = new String(data, StandardCharsets.UTF_8);\n        System.out.println(&quot;String: &quot; + dataString);\n\n        \/\/ 2) String \u2192 byte array (encodings)\n        String name = &quot;Ningkong&quot;;\n\n        byte[] gbk = name.getBytes(Charset.forName(&quot;GBK&quot;));\n        System.out.println(&quot;GBK bytes:  &quot; + Arrays.toString(gbk));\n\n        byte[] utf8 = name.getBytes(StandardCharsets.UTF_8);\n        System.out.println(&quot;UTF-8 bytes:&quot; + Arrays.toString(utf8));\n    }\n}\n<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-588fa0b2');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"253\" src=\"https:\/\/support.nullflag.com\/wp-content\/uploads\/2025\/09\/image-20220127173504514-7625739-1024x253.png\" alt=\"\" class=\"wp-image-64\" srcset=\"https:\/\/www.nullflag.com\/support\/wp-content\/uploads\/2025\/09\/image-20220127173504514-7625739-1024x253.png 1024w, https:\/\/www.nullflag.com\/support\/wp-content\/uploads\/2025\/09\/image-20220127173504514-7625739-300x74.png 300w, https:\/\/www.nullflag.com\/support\/wp-content\/uploads\/2025\/09\/image-20220127173504514-7625739-768x190.png 768w, https:\/\/www.nullflag.com\/support\/wp-content\/uploads\/2025\/09\/image-20220127173504514-7625739-1536x380.png 1536w, https:\/\/www.nullflag.com\/support\/wp-content\/uploads\/2025\/09\/image-20220127173504514-7625739-2048x506.png 2048w, https:\/\/www.nullflag.com\/support\/wp-content\/uploads\/2025\/09\/image-20220127173504514-7625739-360x89.png 360w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<p>Requirement (Reverse Engineering Context)<br>Task: In a certain app\u2019s reverse engineering, you obtain a Java byte array like [-50, -28, -59, -26, -58, -21].<br>Convert this signed-Java-byte array into a string using Python.<\/p>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-okc07ou\"\n     id=\"betterdocs-code-snippet-okc07ou\"\n     data-language=\"javascript\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\ud83d\udcc4<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">Descreption<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-okc07ou .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-javascript\"><code>Java byte range: -128 ~ 127 (signed)\nPython byte range: 0 ~ 255 (unsigned)\n\n\nMapping idea:\n\n  Java  0  1   2  3  4 .. 127 -128 -127 -126    -3  -2  -1     \nPython  0  1   2  3  4 .. 127  128  129  130 ...253 254 255\n\n\nbyte_list = [-50,-28,-59,-26,-58,-21]\n\n\n\u201cConvert the numbers into bytes and concatenate them into a bytearray.\u201d<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-okc07ou');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-7ee80eb1\"\n     id=\"betterdocs-code-snippet-7ee80eb1\"\n     data-language=\"python\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\ud83d\udc0d<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">Python helper : convert signed-Java-bytes \u2192 Python bytes \u2192 decode<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-7ee80eb1 .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-python\"><code>def java_bytes_to_str(jbytes, encoding=&quot;utf-8&quot;, errors=&quot;strict&quot;):\n    &quot;&quot;&quot;\n    Convert a list of signed Java bytes (-128..127) into a Python str\n    using the specified encoding (e.g., &#039;utf-8&#039;, &#039;gbk&#039;).\n    &quot;&quot;&quot;\n    # Map signed [-128..127] -&gt; unsigned [0..255]\n    unsigned = [(b if b &gt;= 0 else b + 256) for b in jbytes]\n    # Build a bytes-like object and decode\n    return bytearray(unsigned).decode(encoding, errors)\n\n# Examples:\ngbk_list  = [-50, -28, -59, -26, -58, -21]\nutf8_list = [-26, -83, -90, -26, -78, -101, -23, -67, -112]\n\nprint(java_bytes_to_str(gbk_list,  encoding=&quot;gbk&quot;))\nprint(java_bytes_to_str(utf8_list, encoding=&quot;utf-8&quot;))\n\n\n\n# bytearray(...).decode(...) is valid; you can also use bytes(...).decode(...).\n\n# If you\u2019re unsure of the charset, try utf-8 first (Android strings are commonly UTF-8), otherwise test gbk, utf-16le, etc.<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-7ee80eb1');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-b65fd584\"\n     id=\"betterdocs-code-snippet-b65fd584\"\n     data-language=\"python\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\ud83d\udc0d<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">GBK example<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-b65fd584 .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-python\"><code>byte_list = [-50, -28, -59, -26, -58, -21]\nbs = bytearray()\nfor item in byte_list:\n    if item &lt; 0:\n        item += 256\n    bs.append(item)\n\ntext = bs.decode(&#039;gbk&#039;)\nprint(text)\n<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-b65fd584');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-bcb4071c\"\n     id=\"betterdocs-code-snippet-bcb4071c\"\n     data-language=\"python\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\ud83d\udc0d<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">UTF-8 example<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-bcb4071c .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-python\"><code>data_list = [-26, -83, -90, -26, -78, -101, -23, -67, -112]\nbs = bytearray()\nfor item in data_list:\n    if item &lt; 0:\n        item += 256\n    bs.append(item)\n\ntext = bs.decode(&#039;utf-8&#039;)\nprint(text)\n<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-bcb4071c');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<h3 class=\"wp-block-heading\">Java side notes: char and String<\/h3>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-cd2ad8k\"\n     id=\"betterdocs-code-snippet-cd2ad8k\"\n     data-language=\"java\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\u2615<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">Char (character) \u2014 single quotes in Java<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-cd2ad8k .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-java\"><code>char v1 = &#039;x&#039;;\nchar v2 = &#039;Ning&#039;;\n<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-cd2ad8k');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-a26e59d8\"\n     id=\"betterdocs-code-snippet-a26e59d8\"\n     data-language=\"java\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\u2615<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">String \u2014 double quotes in Java<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-a26e59d8 .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-java\"><code>String = &quot;NingKong&quot;;<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-a26e59d8');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<p><strong>Reminder:<\/strong> A string is composed of <strong>multiple characters<\/strong> (not \u201cmultiple strings\u201d).<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">Reconstructing Java strings from bytes\/chars<\/h3>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-22c8d980\"\n     id=\"betterdocs-code-snippet-22c8d980\"\n     data-language=\"java\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\u2615<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">java<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-22c8d980 .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-java\"><code>import java.io.UnsupportedEncodingException;\n\npublic class Hello {\n    public static void main(String[] args) throws UnsupportedEncodingException {\n        String v1 = &quot;NingKong&quot;;\n        String v2 = new String(&quot;NingKong&quot;); \/\/ same content\n\n        \/\/ From raw bytes (assumed UTF-8)\n        String v4 = new String(new byte[]{-26, -83, -90, -26, -78, -101, -23, -67, -112}, &quot;UTF-8&quot;);\n\n        \/\/ From raw bytes (GBK)\n        String v5 = new String(new byte[]{-50, -28, -59, -26, -58, -21}, &quot;GBK&quot;);\n\n        \/\/ From chars\n        String v6 = new String(new char[]{&#039;Ning&#039;, &#039;Kong&#039;, &#039;Kang&#039;});\n    }\n}\n<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-22c8d980');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<p>Common String APIs (quick reference):<\/p>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-5b10659f\"\n     id=\"betterdocs-code-snippet-5b10659f\"\n     data-language=\"java\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\u2615<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">java<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-5b10659f .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-java\"><code>public class Hello {\n    public static void main(String[] args) {\n        String origin = &quot;This is a big question&quot;;     \/\/ Define original string\n\n        char    c  = origin.charAt(5);     \/\/ Get character at index 5\n        int     n  = origin.length();      \/\/ Get string length\n        for (int i = 0; i &lt; n; i++) {     \/\/ Iterate through each character\n            char ch = origin.charAt(i);    \/\/ Get character at current position\n        }\n\n        String t  = origin.trim();         \/\/ Remove leading\/trailing whitespace\n        String lo = origin.toLowerCase();  \/\/ Convert to lowercase\n        String up = origin.toUpperCase();  \/\/ Convert to uppercase\n        String[] sp = origin.split(&quot; &quot;);     \/\/ Split by spaces\n        String rep = origin.replace(&quot;big&quot;, &quot;small&quot;); \/\/ Replace word\n        String sub = origin.substring(5, 10);   \/\/ Extract substring [5,10)\n        boolean eq = origin.equals(&quot;This is a big question&quot;);  \/\/ String equality comparison\n        boolean ct = origin.contains(&quot;question&quot;);   \/\/ Check if contains substring\n        boolean sw = origin.startsWith(&quot;This&quot;);  \/\/ Check if starts with specified text\n        String  cat = origin.concat(&quot;Hello&quot;); \/\/ String concatenation\n    }\n}<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-5b10659f');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-6744d287\"\n     id=\"betterdocs-code-snippet-6744d287\"\n     data-language=\"python\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\ud83d\udc0d<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">python<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-6744d287 .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-python\"><code>name = &#039;Alice&#039;\nif name == &#039;funny&#039;:\n    pass<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-6744d287');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<p> String concatenation<\/p>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-1e3864f7\"\n     id=\"betterdocs-code-snippet-1e3864f7\"\n     data-language=\"java\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\u2615<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">java<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-1e3864f7 .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-java\"><code>import java.io.UnsupportedEncodingException;\n\npublic class Hello {\n\n    public static void main(String[] args) {\n        \/\/ &quot;name=alice&amp;age=29&quot;\n        StringBuilder sb = new StringBuilder();  \/\/ StringBuffer is thread-safe, StringBuilder is faster\n        sb.append(&quot;name&quot;);\n        sb.append(&quot;=&quot;);\n        sb.append(&quot;alice&quot;);\n        sb.append(&quot;&amp;&quot;);\n        sb.append(&quot;age&quot;);\n        sb.append(&quot;=&quot;);\n        sb.append(&quot;19&quot;);\n        \n        String dataString = sb.toString();\n        \n        System.out.println(dataString);\n    }\n}\n<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-1e3864f7');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-e8abae38\"\n     id=\"betterdocs-code-snippet-e8abae38\"\n     data-language=\"python\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\ud83d\udc0d<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">python<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-e8abae38 .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-python\"><code>data = []\ndata.append(&quot;name&quot;)\ndata.append(&quot;=&quot;)\ndata.append(&quot;18&quot;)\ndata_string = &quot;&quot;.join(data)<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-e8abae38');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"261\" src=\"https:\/\/support.nullflag.com\/wp-content\/uploads\/2025\/09\/image-20220127174147151-7625739-1024x261.png\" alt=\"\" class=\"wp-image-65\" srcset=\"https:\/\/www.nullflag.com\/support\/wp-content\/uploads\/2025\/09\/image-20220127174147151-7625739-1024x261.png 1024w, https:\/\/www.nullflag.com\/support\/wp-content\/uploads\/2025\/09\/image-20220127174147151-7625739-300x76.png 300w, https:\/\/www.nullflag.com\/support\/wp-content\/uploads\/2025\/09\/image-20220127174147151-7625739-768x195.png 768w, https:\/\/www.nullflag.com\/support\/wp-content\/uploads\/2025\/09\/image-20220127174147151-7625739-1536x391.png 1536w, https:\/\/www.nullflag.com\/support\/wp-content\/uploads\/2025\/09\/image-20220127174147151-7625739-2048x521.png 2048w, https:\/\/www.nullflag.com\/support\/wp-content\/uploads\/2025\/09\/image-20220127174147151-7625739-360x92.png 360w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"257\" src=\"https:\/\/support.nullflag.com\/wp-content\/uploads\/2025\/09\/image-20220127173632438-7625739-1024x257.png\" alt=\"\" class=\"wp-image-66\" srcset=\"https:\/\/www.nullflag.com\/support\/wp-content\/uploads\/2025\/09\/image-20220127173632438-7625739-1024x257.png 1024w, https:\/\/www.nullflag.com\/support\/wp-content\/uploads\/2025\/09\/image-20220127173632438-7625739-300x75.png 300w, https:\/\/www.nullflag.com\/support\/wp-content\/uploads\/2025\/09\/image-20220127173632438-7625739-768x193.png 768w, https:\/\/www.nullflag.com\/support\/wp-content\/uploads\/2025\/09\/image-20220127173632438-7625739-1536x386.png 1536w, https:\/\/www.nullflag.com\/support\/wp-content\/uploads\/2025\/09\/image-20220127173632438-7625739-2048x514.png 2048w, https:\/\/www.nullflag.com\/support\/wp-content\/uploads\/2025\/09\/image-20220127173632438-7625739-360x90.png 360w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"311\" src=\"https:\/\/support.nullflag.com\/wp-content\/uploads\/2025\/09\/image-20220127173906405-7625739-1024x311.png\" alt=\"\" class=\"wp-image-67\" srcset=\"https:\/\/www.nullflag.com\/support\/wp-content\/uploads\/2025\/09\/image-20220127173906405-7625739-1024x311.png 1024w, https:\/\/www.nullflag.com\/support\/wp-content\/uploads\/2025\/09\/image-20220127173906405-7625739-300x91.png 300w, https:\/\/www.nullflag.com\/support\/wp-content\/uploads\/2025\/09\/image-20220127173906405-7625739-768x234.png 768w, https:\/\/www.nullflag.com\/support\/wp-content\/uploads\/2025\/09\/image-20220127173906405-7625739-1536x467.png 1536w, https:\/\/www.nullflag.com\/support\/wp-content\/uploads\/2025\/09\/image-20220127173906405-7625739-2048x623.png 2048w, https:\/\/www.nullflag.com\/support\/wp-content\/uploads\/2025\/09\/image-20220127173906405-7625739-360x109.png 360w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<h3 class=\"wp-block-heading\">Array<\/h3>\n\n\n\n<p>Stores a fixed number of elements.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>It is a container \u2014 it can hold multiple items.<\/li>\n\n\n\n<li>Fixed length: once created, the size cannot be changed.<\/li>\n\n\n\n<li>Specific type: all elements must be of the same data type.<\/li>\n<\/ul>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-21940ffe\"\n     id=\"betterdocs-code-snippet-21940ffe\"\n     data-language=\"java\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\u2615<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">java<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-21940ffe .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-java\"><code>import java.util.Arrays;\n\npublic class Hello {\n    public static void main(String[] args) {\n        \n        \/\/ Example 1: Create an int array with fixed length\n        int[] numArray = new int[3]; \/\/ create a new int array of length 3\n        numArray[0] = 123;   \/\/ assign value\n        numArray[1] = 1;     \/\/ assign value\n        numArray[2] = 999;   \/\/ assign value\n        \n        \/\/ Print array contents\n        System.out.println(Arrays.toString(numArray));  \/\/ Output: [123, 1, 999]\n\n        \/\/ Example 2: Create a String array with initialization\n        String[] names = new String[]{&quot;NingKong&quot;, &quot;Alex&quot;, &quot;Eric&quot;};\n        System.out.println(Arrays.toString(names));  \/\/ Output: [NingKong, Alex, Eric]\n\n        \/\/ Example 3: Simpler way to create a String array\n        String[] nameArray = {&quot;NingKong&quot;, &quot;Alex&quot;, &quot;Eric&quot;};\n        System.out.println(Arrays.toString(nameArray));\n\n        \/\/ Access elements\n        System.out.println(nameArray[0]);   \/\/ Output: NingKong\n        System.out.println(nameArray.length); \/\/ Output: 3\n\n        \/\/ Loop through the array\n        for (int idx = 0; idx &lt; nameArray.length; idx++) {\n            String item = nameArray[idx];\n            System.out.println(&quot;Element at index &quot; + idx + &quot;: &quot; + item);\n        }\n    }\n}\n<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-21940ffe');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<p>Note: Once an array is created, its size cannot be changed. (In Java, arrays are of fixed length.)<\/p>\n\n\n\n<p>In other languages, there are mechanisms for dynamic resizing, reallocation, and migration of data. For example, in Java, Python, and Go, developers often need to understand how arrays (or array-like structures) work in order to handle expansion and dynamic data growth properly.<\/p>\n\n\n\n<h3 class=\"wp-block-heading\">About Object<\/h3>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-897c67e5\"\n     id=\"betterdocs-code-snippet-897c67e5\"\n     data-language=\"javascript\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\ud83d\udcc4<\/span>\n                                            <\/div>\n                \n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-897c67e5 .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-javascript\"><code>In Python, every class implicitly inherits from the object class. That means all classes are subclasses of object.\n\nIn Java, all classes also implicitly inherit from the Object class.\n\nint v1 = 123;\nString name = &quot;NingKong&quot;;\n\nA base class (or parent class) can be used to represent the type of its subclasses.\n\nIn other words, a parent class reference can point to an instance of a subclass.\n\n\nThis concept allows polymorphism, \nmaking it possible to write code that can handle objects of many different types in a uniform way, \nas long as they share the same parent.<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-897c67e5');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-224b6b0a\"\n     id=\"betterdocs-code-snippet-224b6b0a\"\n     data-language=\"java\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\u2615<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">java<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-224b6b0a .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-java\"><code>import sun.lwawt.macosx.CSystemTray;\n\nimport java.util.Arrays;\n\npublic class Hello {\n\n    public static void main(String[] args) {\n        \/\/ String v1 = &quot;wupeiqi&quot;;\n        Object v1 = new String(&quot;NingKong&quot;);\n        System.out.println(v1);\n        System.out.println(v1.getClass());\n\n        Object v2 = 123;\n        System.out.println(v2);\n        System.out.println(v2.getClass());\n    }\n}<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-224b6b0a');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-d9d2b895\"\n     id=\"betterdocs-code-snippet-d9d2b895\"\n     data-language=\"java\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\u2615<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">python<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-d9d2b895 .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-java\"><code>In Java, all types inherit from the Object class.\nThat means a parent class reference (Object) can point to a child class object (like String or Integer).\n\npublic class Main {\n    public static void main(String[] args) {\n        int v1 = 123;  \n        Object v10 = 123;   \/\/ auto-boxed into Integer, stored as Object\n\n        String v2 = new String(&quot;root&quot;);\n        v2.trim();          \/\/ String-specific method\n\n        Object v3 = new String(&quot;root&quot;);\n        v3.hashCode();      \/\/ can only call methods from Object\n\n        \/\/ Cast Object back to String\n        String v4 = (String) v3;\n        v4.trim();          \/\/ now we can call String-specific methods\n    }\n}\n\n    \nAll classes in Java extend Object.\n\nA variable declared as Object can store any object, but you can only use methods defined in Object (like hashCode(), toString(), equals() \u2026).\n\nTo use child-class-specific methods (e.g., String.trim()), you must cast the Object reference back to its actual type.\n<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-d9d2b895');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-f716d37f\"\n     id=\"betterdocs-code-snippet-f716d37f\"\n     data-language=\"java\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\u2615<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">java<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-f716d37f .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-java\"><code>import sun.lwawt.macosx.CSystemTray;   \/\/ (not needed here, can be removed)\n\nimport java.util.Arrays;\n\npublic class Hello {\n\n    public static void main(String[] args) {\n        \/\/ Declare an array: elements must be of type int\n        int[] v1 = new int[3];\n\n        \/\/ Declare an array: elements must be of type String\n        String[] v2 = new String[3];\n\n        \/\/ Declare an array: elements can be of type int\/String (any Object)\n        Object[] v3 = new Object[3];\n        v3[0] = 123;        \/\/ autoboxed into Integer\n        v3[1] = &quot;NingKong&quot;;  \/\/ String\n    }\n}\n<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-f716d37f');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<p>So, if you want to declare an array that can hold mixed types, you can use Object in Java.<\/p>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-9a70ef65\"\n     id=\"betterdocs-code-snippet-9a70ef65\"\n     data-language=\"java\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\u2615<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">Mixed-Type Arrays with Object<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-9a70ef65 .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-java\"><code>import java.util.Arrays;\n\npublic class Hello {\n\n    public static void main(String[] args) {\n        \/\/ v1 is explicitly a String object\n        String v1 = new String(&quot;NingKong&quot;);\n        String res = v1.toUpperCase();\n        System.out.println(res);   \/\/ Output: NINGKONG\n\n        \/\/ v2 is stored as Object, but its actual type is String\n        Object v2 = new String(&quot;NingKong&quot;);\n        String data = (String) v2;   \/\/ cast back to String\n        System.out.println(data.toUpperCase());  \/\/ Output: NINGKONG\n    }\n}\n<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-9a70ef65');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-017b1122\"\n     id=\"betterdocs-code-snippet-017b1122\"\n     data-language=\"java\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\u2615<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">Using instanceof for Type Checking<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-017b1122 .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-java\"><code>import java.util.Arrays;\n\npublic class Hello {\n\n    public static void func(Object v1) {\n        \/\/ System.out.println(v1);\n        \/\/ System.out.println(v1.getClass());  \/\/ check the runtime class\n        \/\/ v1 instanceof Integer  \/\/ check specific type\n\n        if (v1 instanceof Integer) {\n            System.out.println(&quot;Integer type&quot;);\n        } else if (v1 instanceof String) {\n            System.out.println(&quot;String type&quot;);\n        } else {\n            System.out.println(&quot;Unknown type&quot;);\n        }\n    }\n\n    public static void main(String[] args) {\n        func(123);      \/\/ prints: Integer type\n        func(&quot;123&quot;);    \/\/ prints: String type\n\n        \/\/ Object array with mixed types\n        Object[] data = new Object[]{&quot;root&quot;, &quot;alex&quot;, 123};\n\n        \/\/ Force cast from Object to String\n        String v2 = (String) data[0];\n        System.out.println(v2);    \/\/ Output: root\n\n        \/\/ Inspect actual runtime type\n        Object v3 = data[0];\n        System.out.println(v3.getClass().toString()); \/\/ Output: class java.lang.String\n    }\n}\n<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-017b1122');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<ul class=\"wp-block-list\">\n<li>In Java, all classes inherit from Object, and Object represents all types.<\/li>\n\n\n\n<li>\u201cCreate relationships by yourself\u201d<\/li>\n<\/ul>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"1024\" height=\"296\" src=\"https:\/\/support.nullflag.com\/wp-content\/uploads\/2025\/09\/image-20220127224643681-7625739-1024x296.png\" alt=\"\" class=\"wp-image-68\" srcset=\"https:\/\/www.nullflag.com\/support\/wp-content\/uploads\/2025\/09\/image-20220127224643681-7625739-1024x296.png 1024w, https:\/\/www.nullflag.com\/support\/wp-content\/uploads\/2025\/09\/image-20220127224643681-7625739-300x87.png 300w, https:\/\/www.nullflag.com\/support\/wp-content\/uploads\/2025\/09\/image-20220127224643681-7625739-768x222.png 768w, https:\/\/www.nullflag.com\/support\/wp-content\/uploads\/2025\/09\/image-20220127224643681-7625739-1536x444.png 1536w, https:\/\/www.nullflag.com\/support\/wp-content\/uploads\/2025\/09\/image-20220127224643681-7625739-2048x592.png 2048w, https:\/\/www.nullflag.com\/support\/wp-content\/uploads\/2025\/09\/image-20220127224643681-7625739-360x104.png 360w\" sizes=\"auto, (max-width: 1024px) 100vw, 1024px\" \/><\/figure>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-3909703e\"\n     id=\"betterdocs-code-snippet-3909703e\"\n     data-language=\"java\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\u2615<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">java<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-3909703e .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-java\"><code>ArrayList v1 = new ArrayList();\nLinkedList v2 = new LinkedList();<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-3909703e');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-31b86ca1\"\n     id=\"betterdocs-code-snippet-31b86ca1\"\n     data-language=\"java\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\u2615<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">java<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-31b86ca1 .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-java\"><code>List v1 = new ArrayList();\nList v2 = new LinkedList();<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-31b86ca1');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-ade3e1c9\"\n     id=\"betterdocs-code-snippet-ade3e1c9\"\n     data-language=\"java\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\u2615<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">java<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-ade3e1c9 .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-java\"><code>Object v1 = new ArrayList();\nObject v2 = new LinkedList();<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-ade3e1c9');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n\n\n\n<div class=\"betterdocs-code-snippet-wrapper theme-light betterdocs-code-snippet-5b2a3a47\"\n     id=\"betterdocs-code-snippet-5b2a3a47\"\n     data-language=\"java\"\n     data-copy-button=\"true\">\n\n            <div class=\"betterdocs-code-snippet-header betterdocs-file-preview-header\">\n        <div class=\"betterdocs-file-preview-left\">\n                            <div class=\"betterdocs-traffic-lights\">\n                    <span class=\"traffic-light traffic-light-red\"><\/span>\n                    <span class=\"traffic-light traffic-light-yellow\"><\/span>\n                    <span class=\"traffic-light traffic-light-green\"><\/span>\n                <\/div>\n            \n            <div class=\"betterdocs-file-info\">\n                                    <div class=\"betterdocs-file-icon\">\n                                                    <span class=\"betterdocs-file-icon-emoji\">\u2615<\/span>\n                                            <\/div>\n                \n                                    <div class=\"betterdocs-file-name\">\n                        <span class=\"file-name-text\">java<\/span>\n                    <\/div>\n                            <\/div>\n        <\/div>\n\n        <div class=\"betterdocs-file-preview-right\">\n                            <div class=\"betterdocs-code-snippet-copy-container\">\n                    <button class=\"betterdocs-code-snippet-copy-button\"\n                            type=\"button\"\n                            data-clipboard-target=\"#betterdocs-code-snippet-5b2a3a47 .betterdocs-code-snippet-code code\"\n                            aria-label=\"Copy code to clipboard\">\n                        <svg width=\"16\" height=\"16\" viewBox=\"0 0 24 24\" fill=\"none\" xmlns=\"http:\/\/www.w3.org\/2000\/svg\">\n                            <path d=\"M16 1H4C2.9 1 2 1.9 2 3V17H4V3H16V1ZM19 5H8C6.9 5 6 5.9 6 7V21C6 22.1 6.9 23 8 23H19C20.1 23 21 22.1 21 21V7C21 5.9 20.1 5 19 5ZM19 21H8V7H19V21Z\" fill=\"currentColor\"\/>\n                        <\/svg>\n                    <\/button>\n                                    <\/div>\n                    <\/div>\n        <\/div>\n    \n    <div class=\"betterdocs-code-snippet-content\">\n        \n        <pre class=\"betterdocs-code-snippet-code language-java\"><code>class Base {   \/\/ Methods in parent and child classes can be adapted and called\n    public void f2() {\n        System.out.println(&quot;Base--F2&quot;);\n    }\n}\n\nclass Dog extends Base {\n    @Override\n    public void f2() {\n        System.out.println(&quot;Dog&quot;);\n    }\n}\n\nclass Cat extends Base {\n    @Override\n    public void f2() {\n        System.out.println(&quot;Cat&quot;);\n    }\n}\n\npublic class Hello {\n    \/\/ Base here is a generic reference for its subclasses.\n    \/\/ The argument could be a Dog, or a Cat, or any other subclass of Base.\n    public static void showInfo(Base obj) {\n        obj.f2();  \/\/ Calls the subclass&#039;s version of f2 (polymorphism)\n    }\n\n    public static void main(String[] args) {\n        Base v1 = new Base();\n        showInfo(v1);   \/\/ Output: Base--F2\n\n        Dog d = new Dog();\n        showInfo(d);    \/\/ Output: Dog\n\n        Cat c = new Cat();\n        showInfo(c);    \/\/ Output: Cat\n    }\n}\n<\/code><\/pre>\n    <\/div>\n<\/div>\n\n<script type=\"text\/javascript\">\ndocument.addEventListener('DOMContentLoaded', function() {\n    \/\/ Initialize copy functionality for this specific snippet\n    const snippet = document.getElementById('betterdocs-code-snippet-5b2a3a47');\n    if (snippet && window.BetterDocsCodeSnippet) {\n        window.BetterDocsCodeSnippet.initCopyButton(snippet);\n    }\n});\n<\/script>\n","protected":false},"excerpt":{"rendered":"<p>Basic Syntax Initial Code Analysis: hello.java Main function &amp; the entry point of the program. FileName Class Naming Class modifiers: public, default (if omitted).Member modifiers inside classes: public, private, protected, default (if omitted).Static members can be called directly without instantiation. void indicates that a method does not return a value.If a method does return a&#8230;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","template":"","meta":{"_kad_blocks_custom_css":"","_kad_blocks_head_custom_js":"","_kad_blocks_body_custom_js":"","_kad_blocks_footer_custom_js":"","_kad_post_transparent":"","_kad_post_title":"","_kad_post_layout":"default","_kad_post_sidebar_id":"","_kad_post_content_style":"default","_kad_post_vertical_padding":"","_kad_post_feature":"","_kad_post_feature_position":"","_kad_post_header":false,"_kad_post_footer":false,"_kad_post_classname":"","footnotes":""},"doc_category":[15],"glossaries":[],"doc_tag":[],"knowledge_base":[12],"class_list":["post-61","docs","type-docs","status-publish","hentry","doc_category-java_basic","knowledge_base-cpp_c_java_arm64_javascript"],"year_month":"2026-05","word_count":346,"total_views":"372","reactions":{"happy":"0","normal":"0","sad":"0"},"author_info":{"display_name":"sandbox","author_link":"https:\/\/www.nullflag.com\/support\/author\/sandbox\/"},"doc_category_info":[{"term_name":"Java Basic Knowledge","term_url":"https:\/\/www.nullflag.com\/support\/kb\/cpp_c_java_arm64_javascript\/java_basic\/"}],"doc_tag_info":[],"taxonomy_info":{"doc_category":[{"value":15,"label":"Java Basic Knowledge"}],"knowledge_base":[{"value":12,"label":"Cpp\/C\/Java\/Arm64ASM\/JavaScript"}]},"featured_image_src_large":false,"comment_info":0,"knowledge_base_info":[{"term_name":"Cpp\/C\/Java\/Arm64ASM\/JavaScript","term_url":"https:\/\/www.nullflag.com\/support\/kb\/cpp_c_java_arm64_javascript\/","term_slug":"cpp_c_java_arm64_javascript"}],"knowledge_base_slug":["cpp_c_java_arm64_javascript"],"_links":{"self":[{"href":"https:\/\/www.nullflag.com\/support\/wp-json\/wp\/v2\/docs\/61","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.nullflag.com\/support\/wp-json\/wp\/v2\/docs"}],"about":[{"href":"https:\/\/www.nullflag.com\/support\/wp-json\/wp\/v2\/types\/docs"}],"author":[{"embeddable":true,"href":"https:\/\/www.nullflag.com\/support\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.nullflag.com\/support\/wp-json\/wp\/v2\/comments?post=61"}],"version-history":[{"count":12,"href":"https:\/\/www.nullflag.com\/support\/wp-json\/wp\/v2\/docs\/61\/revisions"}],"predecessor-version":[{"id":567,"href":"https:\/\/www.nullflag.com\/support\/wp-json\/wp\/v2\/docs\/61\/revisions\/567"}],"wp:attachment":[{"href":"https:\/\/www.nullflag.com\/support\/wp-json\/wp\/v2\/media?parent=61"}],"wp:term":[{"taxonomy":"doc_category","embeddable":true,"href":"https:\/\/www.nullflag.com\/support\/wp-json\/wp\/v2\/doc_category?post=61"},{"taxonomy":"glossaries","embeddable":true,"href":"https:\/\/www.nullflag.com\/support\/wp-json\/wp\/v2\/glossaries?post=61"},{"taxonomy":"doc_tag","embeddable":true,"href":"https:\/\/www.nullflag.com\/support\/wp-json\/wp\/v2\/doc_tag?post=61"},{"taxonomy":"knowledge_base","embeddable":true,"href":"https:\/\/www.nullflag.com\/support\/wp-json\/wp\/v2\/knowledge_base?post=61"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}