# Java 關鍵字 > 原文： [https://howtodoinjava.com/java-keywords/](https://howtodoinjava.com/java-keywords/) Java 關鍵字是 50 個保留字，在應用程序代碼中具有非常特定的含義。 程序員不應將這些關鍵字用于其預期的其他目的。 ## 1\. Java 關鍵字特性 * 給定的是列表具有所有保留的 java 關鍵字。 我們不能在程序中使用以下任何內容作為標識符。 * 關鍵字`const`和`goto`被保留，即使它們當前未被使用。 * `true`，`false`和`null`看起來像關鍵字，但它們實際上是字面值。 我們不能在程序中使用它們作為標識符。 * `strictfp`已在 JDK 1.2 中添加。 * `assert`已在 JDK 1.4 中添加。 * `enum`已在 JDK 1.5 中添加。 ## 2\. Java 關鍵字列表 | | | | | | | --- | --- | --- | --- | --- | | [`abstract`](https://howtodoinjava.com/java/basics/abstract-keyword/) | [`continue`](https://howtodoinjava.com/java/basics/continue-keyword-statement-in-java/) | [`for`](https://howtodoinjava.com/java/basics/for-loop-in-java/) | `new` | [`switch`](https://howtodoinjava.com/java/basics/switch-statement-in-java/) | | [`assert`](https://howtodoinjava.com/java/basics/java-assert/) | [`default`](https://howtodoinjava.com/java8/default-methods-in-java-8/) | `goto` | `package` | [`synchronized`](https://howtodoinjava.com/java/multi-threading/java-synchronized/) | | [`boolean`](https://howtodoinjava.com/java/basics/java-boolean/) | [`do`](https://howtodoinjava.com/java/basics/do-while-loop-in-java/) | [`if`](https://howtodoinjava.com/java/basics/if-else-statement-in-java/) | [`private`](https://howtodoinjava.com/oops/java-access-modifiers/) | [`this`](https://howtodoinjava.com/java/basics/this-vs-super/) | | [`break`](https://howtodoinjava.com/java/basics/break-keyword-statement-in-java/) | `double` | [`implements`](https://howtodoinjava.com/oops/extends-vs-implements/) | [`protected`](https://howtodoinjava.com/oops/java-access-modifiers/) | [`throw`](https://howtodoinjava.com/java/exception-handling/throw-vs-throws/) | | `byte` | [`else`](https://howtodoinjava.com/java/basics/if-else-statement-in-java/) | `import` | [`public`](https://howtodoinjava.com/oops/java-access-modifiers/) | [`throws`](https://howtodoinjava.com/java/exception-handling/throw-vs-throws/) | | [`case`](https://howtodoinjava.com/java/basics/switch-statement-in-java/) | [`enum`](https://howtodoinjava.com/java/enum/guide-for-understanding-enum-in-java/) | [`instanceof`](https://howtodoinjava.com/oops/java-instanceof/) | `return` | [`transient`](https://howtodoinjava.com/java/basics/transient-keyword-in-java-with-real-time-example/) | | [`catch`](https://howtodoinjava.com/java/exception-handling/try-catch-finally/) | [`extends`](https://howtodoinjava.com/oops/extends-vs-implements/) | `int` | `short` | [`try`](https://howtodoinjava.com/java/exception-handling/try-catch-finally/) | | `char` | [`final`](https://howtodoinjava.com/java/basics/final-finally-finalize/) | `interface` | [`static`](https://howtodoinjava.com/java/basics/java-static-keyword/) | `void` | | `class` | [`finally`](https://howtodoinjava.com/java/exception-handling/try-catch-finally/) | `long` | [`strictfp`](https://howtodoinjava.com/java/basics/strictfp-modifier/) | `volatile` | | `const` | `float` | `native` | [`super`](https://howtodoinjava.com/java/basics/this-vs-super/) | [`while`](https://howtodoinjava.com/java/basics/while-loop-in-java/) | 無法在單個頁面中了解所有關鍵字。 我們將在專用教程中了解每個 Java 關鍵字。 學習愉快！