hi,
When I am debugging and stepping through a program, and try to execute the "importPreferences(FileInputStream)" method of class java.util.prefs.Preferences, I see a page for the class "URLClassPath.class". It mentions that the source attachment does not contain the source for the file URLClassPath.class. You can change the source attachment by clicking "Change Attached Source" below:

There is a button seen under this with the message "Change Attached Source..."