<<<<<<<<<<<<<<<<<<<< MyClass0a.java >>>>>>>>>>>>>>>>>>>>
import java.io.*;


class MyClass0a {
	public static void main(String[] args) {
		System.out.println("Hello world!");
	}
}
<<<<<<<<<<<<<<<<<<<< MyClass0a.java >>>>>>>>>>>>>>>>>>>>


<<<<<<<<<<<<<<<<<<<< compile and run >>>>>>>>>>>>>>>>>>>>
# javac MyClass0a.java
# java MyClass0a
<<<<<<<<<<<<<<<<<<<< compile and run >>>>>>>>>>>>>>>>>>>>


<<<<<<<<<<<<<<<<<<<< THE ERROR >>>>>>>>>>>>>>>>>>>>
Exception in thread "main" java.lang.UnsupportedClassVersionError: Bad version number in .class file
        at java.lang.ClassLoader.defineClass1(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)
<<<<<<<<<<<<<<<<<<<< THE ERROR >>>>>>>>>>>>>>>>>>>>