java.lang.VerifyError after extending class

I'm extending the JFreeChart ChartComposite class. When I try to create the instance of extended class I'm getting java.lang.VerifyError : .... incompatible object argument for fu开发者_如何学Pythonnction call error.

Practically speacking:

It mostly happens when you are compliing with one version of the library, but running with another version of the library.

More precisely, VerifyError is a type of LinkageError. From the javadoc of LinkageError: "Subclasses of LinkageError indicate that a class has some dependency on another class; however, the latter class has incompatibly changed after the compilation of the former class."

It sounds like you are possibly running against a different version of the JFreeChart JAR than you compiled your code against - does the stack trace contain any information about what the problematic method is?

Another possibility would be that JFreeChart expects a particular version of some 3rd-party library on the classpath whereas you are running with a different version.