For my diploma thesis, I developed a plug-in for Eclipse which provides Delta Debugging of input files.
The goal of the plug-in is to automatically minimize an input file until only the part relevant for a failure remains. For example, a single statement in a huge HTML document might be responsible for a browser crash. With the DDInput plug-in, this huge file can automatically be minimized until only the failure-inducing statement remains. All you need for that to happen is a JUnit test case.
For more information you should read my diploma thesis: A Framework for Delta Debugging in Eclipse (PDF, 1MB).
You can also download the plug-ins DDCore and DDInput which provide the Delta Debugging functionality. They work with Eclipse 3.1 (and hopefully for later versions as well) and need the Java JRE 5. To install the plug-ins, simply unpack the zip-file in your Eclipse directory; subfolders will then be created in your plugin directory.
You can find more information on Delta Debugging here. If you have any questions regarding this subject, just contact me.
A screenshot of the DDInput plug-in in action.