Mockito is a mocking framework (see Two different mocking approaches) that is an offshoot of EasyMock. Whatever the mocking framework one uses, a common feature is the ability to mock interfaces, through the JDK Proxy class. This is well and nice, but one has to explicitly mock every method that one wants to use in the course of the test. What if I want to mock an already existing implementation, with some methods providing behaviours that suit me ?