WebSphere Studio Application Developer part 61 provides integrated development tools for all e-business development roles, including Web developers, Java developers, business analysts, architects, and enterprise programmers. The customizable, targeted, role-based approach of WebSphere Studio Application Developer will be characteristic of all new products built on the WebSphere Studio Workbench. It is well integrated with WebSphere Application Server and provides built-in server test environments that can be used for testing and profiling Web applications | What is JUnit JUnit is an open source testing framework that is used to develop and execute unit tests in Java. It was written by Erich Gamma one of four notable authors who wrote the classic book Design Patterns and Kent Beck who has also written extensively about object development and first described the eXtreme Programming XP software development process. A good starting point for finding information about JUnit on the Web is the JUnit Web site http This site contains documentation and links as well as a free download that includes both the JUnit source and compiled code. Unit testing Unit tests are informal tests that are generally executed by the developers of the application code. They are often quite low-level in nature and test the behavior of individual software components such as individual Java classes servlets or EJBs. Because unit tests are usually written and performed by the application developer they tend to be white-box in nature that is to say they are written using knowledge about the implementation details and test specific code paths. This is not to say all unit tests have to be written this way one common practice is to write the unit tests for a component based on the component specification before developing the component itself. Both approaches are valid and you may want to make use of both when defining your own unit testing policy. Why unit testing On the surface this is a question with a straightforward answer. We test to find defects in our code and to verify that changes we have made to existing code do not break that code. Perhaps it is more useful to look at the question from the opposite perspective that is to say why do developers not perform unit tests In general the simple answer is because it is too hard and because nobody forces them to. Writing an effective set of unit tests for a component is not a trivial undertaking. Given the pressure to deliver that many developers find themselves subjected to the .