Steps to reproduce (with 1.0-groovy-2.0-SNAPSHOT): - create an abstract class, say MyAbstractClass - try to create a global mock for it, GroovyMock(MyAbstractClass, global: true) - see java.lang.InstantiationError being thrown - remove global: true and rerun - no exception is thrown

This defect kind of kills the ability to mock static methods in some cases as frameworks (Atmosphere in my case) quite often provide them on abstract classes.