View Full Version : NetBeans Unsupported major/minor version

June 10th, 2012, 02:42 AM
Hey everyone,

I ran into some issues while trying to compile a really straightforward Java program.

JFrame frame = new JFrame("a frame");
frame.add(new JButton("a button"));
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOS E);
When I compile it, and run it in Netbeans, it works just perfectly, and shows the JFrame and JButton.

When I try to open the .jar it produces (either by right-clicking and selecting "open with openjdk 6 runtime" or "openjdk 7 runtime", or by using the "java -jar" command) it fails.

output of java -jar <filename>
Exception in thread "main" java.lang.UnsupportedClassVersionError: javaapplication1/JavaApplication1 : Unsupported major.minor version 51.0
at java.lang.ClassLoader.defineClass1(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java :634)
at java.security.SecureClassLoader.defineClass(Secure ClassLoader.java:142)
at java.net.URLClassLoader.defineClass(URLClassLoader .java:277)
at java.net.URLClassLoader.access$000(URLClassLoader. java:73)
at java.net.URLClassLoader$1.run(URLClassLoader.java: 212)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.j ava:205)
at java.lang.ClassLoader.loadClass(ClassLoader.java:3 21)
at sun.misc.Launcher$AppClassLoader.loadClass(Launche r.java:294)
at java.lang.ClassLoader.loadClass(ClassLoader.java:2 66)
Could not find the main class: javaapplication1.JavaApplication1. Program will exit.

the output of javac -version:
javac 1.6.0_24

the output of java -version:
java version "1.6.0_24"
OpenJDK Runtime Environment (IcedTea6 1.11.1) (6b24-1.11.1-4ubuntu3)
OpenJDK 64-Bit Server VM (build 20.0-b12, mixed mode)

Can anyone help me out?

Thanks in advance.