Debugging is the process of examining your application for errors. The process of debugging is acomplished by setting breakpoints and watches in your code and running it in the debugger. This enables you to execute your code one line at a time and examine the state of your application in order to discover any problems.
The IDE uses the Sun Microsystems JPDA debugger to debug your programs. When you start a debugging session, all of the relevant debugger windows appear automatically at the bottom of your screen. You can debug an entire project, individual executable classes, and JUnit tests.
The IDE also lets you debug applications that are running on a remote machine by attaching the debugger to the application process.