Bad version in .class file

[jeffypop13]

I pulled down the latest code from SVN and used the new JSBuilder2. This is my first attempt to create a build. I think I have everything set up correctly, but I receive this error immediately after invoking the build:

C:\Development\Workspaces\ExtJs\Builds>java -jar JSBuilder2.jar --projectFile C:\Development\Workspaces\ExtJs\Builds\07302009\Source\ext.jsb2 --homeDir C:\Development\Workspaces\ExtJs\Builds\07302009\deploy

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)

[rockyjacobson]

I'm getting a similar error, too. Anyone know what's up?

[jOmega]

It created-by: 1.6.0_13 (Sun Microsystems Inc.)
the version of the class file is 50.0
perhaps you must use the lasted java

and i found there are some source file is JSBuilder2.jar, you can see it.

[jeffypop13]

I had JRE 1.5.0.
I installed JRE 1.6.0_15 and the build completed successfully. Thanks.