UnsupportedClassVersionError when using core.jar in Eclipse with the G4P library

Contributed Library Questions

erniejuni..

UnsupportedClassVersionError when using core.jar in Eclipse with the G4P library

in Contributed Library Questions • 3 years ago

Hi,

the circumstances are as described in the title. I get the following error:

Exception in thread "Animation Thread" java.lang.UnsupportedClassVersionError: Bad version number in .class file
at java.lang.ClassLoader.defineClass2(Native Method)
at java.lang.ClassLoader.defineClass(ClassLoader.java:775)
at java.security.SecureClassLoader.defineClass(SecureClassLoader.java:160)
at java.net.URLClassLoader.defineClass(URLClassLoader.java:254)
at java.net.URLClassLoader.access$100(URLClassLoader.java:56)
at java.net.URLClassLoader$1.run(URLClassLoader.java:195)
at java.security.AccessController.doPrivileged(Native Method)
at java.net.URLClassLoader.findClass(URLClassLoader.java:188)
at java.lang.ClassLoader.loadClass(ClassLoader.java:317)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:280)
at java.lang.ClassLoader.loadClass(ClassLoader.java:252)
at java.lang.ClassLoader.loadClassInternal(ClassLoader.java:375)
at java.lang.Class.getDeclaredMethods0(Native Method)
at java.lang.Class.privateGetDeclaredMethods(Class.java:2395)
at java.lang.Class.getMethod0(Class.java:2642)
at java.lang.Class.getMethod(Class.java:1579)
at guicomponents.GComponent.createEventHandler(GComponent.java:203)
at guicomponents.GButton.buttonCtorCore(GButton.java:160)
at guicomponents.GButton.<init>(GButton.java:98)
at WLANLocator.setup(WLANLocator.java:34)
at processing.core.PApplet.handleDraw(PApplet.java:1571)
at processing.core.PApplet.run(PApplet.java:1496)
at java.lang.Thread.run(Thread.java:613)

For startup I use this main method:

public static void main(String args[]) {
PApplet.main(new String[] { "--display=1", "WLANLocator" });
}

The error seems to be deep into G4P's event system but I found a strange solution (not realy a solution) to the problem. In my main class (the one derived from PApplet) I defined a method that returns a self defined class. If I remove this method or change the return type to void the error disappears.

I realy need my self defined methods in the main class. I don't know what the two things have to do with each other …. Maybe this is a beginners error but to me it sounds very strange.

Greetings,

erniejunior

Replies(2)

PhiLho

Re: UnsupportedClassVersionError when using core.jar in Eclipse with the G4P library

3 years ago

What version of Java do you have?

And what does your method returning a self defined class (?) looks like?

erniejuni..

Re: UnsupportedClassVersionError when using core.jar in Eclipse with the G4P library

3 years ago

I used Java 1.5. When I used Java 1.6 everything went well. It seems like some libraries I used were compiled for Java 1.6 because I used them in the self defined method. That explains why the error disappeared when I removed the method. Thanks for the help.

Greetings,

erniejunior

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