Verify that you truly need to modify WPILib before beginning. Many desired changes to or extensions of WPILib classes can be made by making a renamed copy of the class in your team code or making a class that extends the WPI class. This approach is often preferable to modifying WPILib as it makes it much easier to integrate any updates to the libraries.

You will want to base your custom WPILibJ project off the source included with the latest plugins. Browse to the USER\sunspotfrcsdk\lib folder, then locate and unzip the wpilibj.project.zip file (Note that the USER directory varies based on the operating system and name of the user, if necessary you should be able to perform a search on your machine to locate the sunspotfrcsdk directory.)

Open Netbeans and select File >> Open Project. Browse to the sunspotfrcsdk\lib folder and select the wpilib.project project, then click Open Project

You now have a copy of the WPILibJ project in Netbeans. Make any code changes you would like, then right click on the project and select Build.

1. To build Robot programs using this custom WPILibJ library, open the Netbeans options by selecting Tools >> Options.
2. Click the Miscellaneous tab on the top ribbon,
3. Then the FRC Configuration tab on the secondary ribbon.
4. Check the box next to Use Alternate WPILibJ library and click Browse. Browse to your custom version of the library (in sunspotfrcsdk\lib\wpilibj.project\dist\lib\wpilibj.jar if you did not move it). then click OK.

Your robot projects will now build using your customized version of WPILibJ. If you have changes, fixes or additions that you think would benefit the FRC community at large, please feel free to submit them as patches via the Bug Tracker on the FIRSTForge WPILib project.