java运行出现JNI错误，JDK8和JDK11都安装了

1. 问题描述

因为编程的需要，所以我安装了JDK8和JDK11，在安装好了之后配置好了环境变量，之后打开Eclipse的时候，却发现一个HelloWorld都没有办法运行了，出现如下的报错：

Exception in thread "main" java.lang.UnsupportedClassVersionError: king/HelloWorld has been compiled by a more recent version of the Java Runtime (class file version 54.0), this version of the Java Runtime only recognizes class file versions up to 52.0

at java.lang.ClassLoader.defineClass1(Native Method)
	at java.lang.ClassLoader.defineClass(ClassLoader.java:756)
	at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:142)
	at java.net.URLClassLoader.defineClass(URLClassLoader.java:468)
	at java.net.URLClassLoader.access$100(URLClassLoader.java:74)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:369)
	at java.net.URLClassLoader$1.run(URLClassLoader.java:363)
	at java.security.AccessController.doPrivileged(Native Method)
	at java.net.URLClassLoader.findClass(URLClassLoader.java:362)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:418)
	at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:355)
	at java.lang.ClassLoader.loadClass(ClassLoader.java:351)
	at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:601)

2. 尝试办法

使用命令行编译也是不行 检查了我的版本之后发现环境变量是没有错误的：

3. 解决办法

看报错的信息是编译器的版本有冲突 king/HelloWorld has been compiled by a more recent version of the Java Runtime (class file version 54.0), this version of the Java Runtime only recognizes class file versions up to 52.0 于是就开始查资料

3.1 解决方法：

Project右键->Properties->Java Compiler->Configure Workspace Setting

3.2 测试结果成功

终于好了，我的HelloWorld测试出来了