Can't find main class in NetBeans 6.9

Question

Whenever I load NetBeans 6.9 (similar errors happened on previous versions also) then I let NetBeans finish scanning my projects and once it's done I try to run a profile which points to a class with a main method, NetBeans always says the main class is not found, even though it shows up in the list of classes once the error pops up.

If I select the class from the list and hit OK, the same error happens again (main class not found).

If I compile the main class, I still get the same problem.

I think I still get the same issue if I rebuild the entire project. -> when I compile the main project it compiles all projects, even those that are closed. What is going on?

The only way I have found so far to work around this is to close the project and re-open it and wait for the project scan to finish again.

This is incredibly annoying. Is there a fix for this?

Another strange thing I noticed is that my project seems to be building into the wrong JAR file name (though if I do the above step of closing and reopening the project it still works). I have two projects with different names, and even after having closed the other project and restarted NetBeans a lot of times, when I build the first project it uses the JAR file name for the second project that has been closed for a long time.

Answer 1

I fixed a very similar behaviour by deleting NetBeans's cache. Delete the folder User\.netbeans\6.9\var\cache\index\.

Windows 7 and Netbeans 7.2: User\AppData\Local\NetBeans\Cache\7.2\index