Using the Debugger Windows

JDeveloper provides a number of special-purpose debugging windows:

The Breakpoints Window displays the breakpoints for the current workspace and project.
The Smart Data Window displays the data which is being used in the code that you are stepping through.
The Data Window displays the arguments and local variables for the current context. Note: Include Debug Information must be selected in the Compiler page of the Project Properties dialog.
The Watches Window displays the values for a watched program. A watch evaluates an expression according to the current context. If you move to a new context, the expression is reevaluated for the new context.
The Inspector Window displays a single data item in its own floating window. An inspector evaluates an expression according to the current context.
The Stack Window displays the call stack for the current thread.
The Classes Window displays information about the classes which have been loaded as your application runs, including the name and package of each class. If you are using OJVM for debugging, the debugger can also display the number of live instances of each class and the amount of memory being consumed by those instances.
The Heap Window displays information about live objects in the Java heap for the program you are debugging. Class folders display all instances of a class and Reference Path folders show you why an object has not been garbage collected. From the Heap window, you can see the heap address for each instance of a given class, as well as determine which other objects are holding references to those instances. This is important when looking for memory leaks; instances being referenced by other objects do not not get garbage collected. The Heap window is only available when you debug with the Oracle Java Virtual Machine (OJVM) which is set in the Run/Debug page of the Project Properties dialog.
The Monitors Window displays information for active monitors in your application, as well as information about the status of threads accessing those monitors. This window is useful for examining deadlocks and other thread synchronization problems. Not all Java Virtual Machines allow the debugger to show information about monitors. For example, OJVM and Sun's Classic JVM have support for debugging monitor information, but Sun's HotSpot JVM does not.
The Threads Window displays the threads and the thread groups, highlights the current thread, and shows the name, status, priority, and group of each thread.

You can open the debugger windows by choosing them from the View then choose Debug Windows menu.

You can control what type of information is displayed in each of the debugger windows. To see what options are available in each window such as which columns to display, right-click in a window and choose Settings from the context menu. Or, you can choose Tools then choose Preferences from the main menu and expand the Debugger node to display a preferences page for each debugger window. You can also save the debug information to either a text or HTML output file. See Exporting Debug Information to File.

For more information, select the debugger window to make it active and press F1 to display its Help topic.