SevenMock is a light-weight Java dynamic mock objects implementation.
It works in a similar way to EasyMock and jMock, but is unusual in that it places responsibility for verifying operation parameters directly on the unit test code by use of expectation call-backs. This enables the test designer to write very clear, precisely targeted tests and makes test failures easier to diagnose - any stacktrace produced will point directly back to test code rather than framework code.
For documentation, support and downloads, see: http://www.sevenmock.org/