java - 线程 “main” java.lang.UnsupportedClassVersionError :HelloWorldApp 中的异常

Question

一个简单的 hello word 程序被编译但是当我运行它时我得到以下异常。

Exception in thread "main" java.lang.UnsupportedClassVersionError: a (Unsupported major.minor version 51.0)
    at java.lang.ClassLoader.defineClass0(Native Method)
    at java.lang.ClassLoader.defineClass(Unknown Source)
    at java.security.SecureClassLoader.defineClass(Unknown Source)
    at java.net.URLClassLoader.defineClass(Unknown Source)
    at java.net.URLClassLoader.access$100(Unknown Source)
    at java.net.URLClassLoader$1.run(Unknown Source)
    at java.security.AccessController.doPrivileged(Native Method)
    at java.net.URLClassLoader.findClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClass(Unknown Source)
    at java.lang.ClassLoader.loadClassInternal(Unknown Source)
    Could not find the main class:HelloWorldApp.Program will exit.

我有 java 版本 1.6.0_21

我的程序是:

class HelloWorldApp { 
   public static void main(String[] args) { 
   System.out.println("Hello World!"); // Display the string. 
   }
}

Answer 1

您为一个版本编译了 .class 并尝试在旧版本上运行它。

How to fix java.lang.UnsupportedClassVersionError: Unsupported major.minor version