How to solve java.lang.NoClassDefFoundError?

Question

I\'ve tried both the example in Oracle\'s Java Tutorials. They both compile fine, but at run-time, both come up with this error:

Exception in thread \"main\"         


        

Answer 1

Don't use test classes outside the module

I do not have a solution, just another flavour of the "present at compilation, absent at run time" case.

I was trying to use a very convenient method from a JUnit test class from another test class which resides in a different module. That's a no-no, since test code is not part of the packaged jar, but I didn't realize because it appears visible for the user class from within Eclipse.

My solution was to place the method in a existing utilities class that is part of the production code.