Class file name must end with .class exception in Java Search

Question

I was hoping someone could help me out with a problem I'm having using the java search function in Eclipse on a particular project.

When using the java search on one particular project, I get an error message saying Class file name must end with .class (see stack trace below). This does not seem to be happening on all projects, just one particular one, so perhaps there's something I should try to get rebuilt?

I have already tried Project -> Clean... and Closing Eclipse, deleting all the built class files and restarting Eclipse to no avail.

The only reference I've been able to find on Google for the problem is at http://www.crazysquirrel.com/computing/java/eclipse/error-during-java-search.jspx, but unfortunately his solution (closing, deleting class files, restarting) did not work for me.

If anyone can suggest something to try, or there's any more info I can gather which might help track it's down, I'd greatly appreciate the pointers.

Version: 3.4.0 Build id: I20080617-2000 

Also just found this thread - http://www.myeclipseide.com/PNphpBB2-viewtopic-t-20067.html - which indicates the same problem may occur when the project name contains a period. Unfortunately, that's not the case in my setup, so I'm still stuck.

Caused by: java.lang.IllegalArgumentException: Class file name must end with .class at org.eclipse.jdt.internal.core.PackageFragment.getClassFile(PackageFragment.java:182) at org.eclipse.jdt.internal.core.util.HandleFactory.createOpenable(HandleFactory.java:109) at org.eclipse.jdt.internal.core.search.matching.MatchLocator.locateMatches(MatchLocator.java:1177) at org.eclipse.jdt.internal.core.search.JavaSearchParticipant.locateMatches(JavaSearchParticipant.java:94) at org.eclipse.jdt.internal.core.search.BasicSearchEngine.findMatches(BasicSearchEngine.java:223) at org.eclipse.jdt.internal.core.search.BasicSearchEngine.search(BasicSearchEngine.java:506) at org.eclipse.jdt.core.search.SearchEngine.search(SearchEngine.java:551) at org.eclipse.jdt.internal.corext.refactoring.RefactoringSearchEngine.internalSearch(RefactoringSearchEngine.java:142) at org.eclipse.jdt.internal.corext.refactoring.RefactoringSearchEngine.search(RefactoringSearchEngine.java:129) at org.eclipse.jdt.internal.corext.refactoring.rename.RenameTypeProcessor.initializeReferences(RenameTypeProcessor.java:594) at org.eclipse.jdt.internal.corext.refactoring.rename.RenameTypeProcessor.doCheckFinalConditions(RenameTypeProcessor.java:522) at org.eclipse.jdt.internal.corext.refactoring.rename.JavaRenameProcessor.checkFinalConditions(JavaRenameProcessor.java:45) at org.eclipse.ltk.core.refactoring.participants.ProcessorBasedRefactoring.checkFinalConditions(ProcessorBasedRefactoring.java:225) at org.eclipse.ltk.core.refactoring.Refactoring.checkAllConditions(Refactoring.java:160) at org.eclipse.jdt.internal.ui.refactoring.RefactoringExecutionHelper$Operation.run(RefactoringExecutionHelper.java:77) at org.eclipse.jdt.internal.core.BatchOperation.executeOperation(BatchOperation.java:39) at org.eclipse.jdt.internal.core.JavaModelOperation.run(JavaModelOperation.java:709) at org.eclipse.core.internal.resources.Workspace.run(Workspace.java:1800) at org.eclipse.jdt.core.JavaCore.run(JavaCore.java:4650) at org.eclipse.jdt.internal.ui.actions.WorkbenchRunnableAdapter.run(WorkbenchRunnableAdapter.java:92) at org.eclipse.jface.operation.ModalContext$ModalContextThread.run(ModalContext.java:121) 

Thanks McDowell, closing and opening the project seems to have fixed it (at least for now).

Answer 1

Comment #9 to bug 269820 explains how to delete the search index, which appears to be the solution to a corrupt index whose symptoms are the dreaded

An internal error occurred during: "Items filtering".
Class file name must end with .class

message box.

How to delete the search index:

1. Close Eclipse
2. Delete <workspace>/.metadata/.plugins/org.eclipse.jdt.core/*.index
3. Delete <workspace>/.metadata/.plugins/org.eclipse.jdt.core/savedIndexNames.txt
4. Start Eclipse again

Answer 2

Two more general-purpose mechanisms for fixing some of Eclipse's idiosyncrasies:

• Close and open the project
• Delete the project (but not from disk!) and reimport it as an existing project

Failing that, bugs.eclipse.org might provide the answer.

If the workspace is caching something broken, you may be able to delete it by poking around in workspace/.metadata/.plugins. Most of that stuff is fairly transient (though backup and watch for deleted preferences).