ClassFormatError

ALERT: java/lang/ClassFormatError: Bad version information.

If when launching a Midlet in netbeans emulator the above errors, then check if any jar file is being used which is created using Java 1.5 and above.

J2ME InvalidJadException 36 while run

Exception:

com.sun.kvem.midletsuite.InvalidJadException: Reason = 36 Error in opening jar file:

Troubleshooting:

Right click on project - Application Descriptor - Attributes

Check if extra attributes other than following are there :

MIDlet-Name

MIDlet-Vendor

MIDlet-Version

If they are present remove those and again build and run.

If problem persists search in forums and add the solutions as a comment in this blog.