JDeveloper bug – ClassNotFound

Every once in a while for no apparent reason a JDeveloper ADF/Struts project gets corrupted. When compiling the project I get an error that a certain class cannot be found. Most of the time it ‘s a struts HTML tag class. When I check my libraries and paths everything seems in perfect order. Very annoying.
One ( ) workaround is to disable automatic compiling before running the web-app. Compile the project by hand and run the web-app, ignoring the errors. But this does not really do the trick. There are other processes in JDeveloper which rely on successfull compilation (for example creating a DataControl).

On the OTN JDeveloper forum Steve Muench suggested backing up the JDEV_HOMEjdevsystem9.0.5.2.1618 directory and then removing it all together. This directory stores user preferences. Apparently something is corrupted there. The directory will be recreated automatically

I took this approach and all seem to be working OK again. Of course I had to re-add all my workspaces again to JDeveloper for them to appear in the navigator. I keep the old directory backed-up just in case