API Usage Scanner: A Java utility that scans Java bytecode to detect references to targeted APIs.
JFeature is an open source feature/requirement coverage tool that facilitates focusing on requirements as you develop code. It lets you leverage from standard development practices to get more insight into the requirements covered by the code. JFeature works on top of the well known unit testing framework - JUnit, to identify the requirement coverage in the code. This also makes JFeature useful for projects, which use tools that operate on top of JUnit, such as, Cactus, StrutsTestcase?, etc.
JMock is a library that supports test-driven development1 of Java2 code with mock objects3. Mock objects help you design and test the interactions between the objects in your programs. jMock makes it quick and easy to define mock objects, so you don't break the rhythm of programming; lets you precisely specify the interactions between your objects, reducing the brittleness of your tests; works well with the autocompletion and refactoring features of your IDE; plugs into your favourite test framework; is easy to extend. http://www.mockobjects.com/
EasyMock provides Mock Objects for interfaces in JUnit tests by generating them on the fly using Java's proxy mechanism. Due to EasyMock?'s unique style of recording expectations, most refactorings will not affect the Mock Objects. So EasyMock? is a perfect fit for Test-Driven Development.
RMock 2.0.0 is a Java mock object framework to use with jUnit. RMock has support for a setup-modify-run-verify workflow when writing jUnit tests. It integrates better with IDE refactoring support and allows designing classes and interfaces in a true test-first fashion.