As an application is built, it is advisable to test it whenever functionality is added, so that errors are caught as early as possible. This makes problems easier to diagnose and correct. This lesson discusses ways to track down application problems and create test cases to improve software quality. It discusses tools to help you troubleshoot Fusion applications, including FileMon, JUnit, ADF Logger, ADF Diagnostics, and the JDeveloper debugger. You also learn how to obtain assistance with JDeveloper and application problems.