FYI: Fix for Eclipse error "The following problem occurred, xyz.jarwas referenced by the classpath,

[Legaia]

I was trying to get an auto generated serial version UID from a new
class, but it kept giving me this error. What was crazy was that the
jars DO exist.

I just wanted to post the solution. Maybe the next time I google I'll
find my own message again - ha!

So anyways, try blowing away your Servers project and recreating. I
also deleted my Eclipse project and did a fresh checkout from SVN for
good measure. Very irritating.

It was a dynamic web project, so I figure the problem is coming from
Web Tools Platform. I've got this message in my log over and over
again, so I suspect this is the root cause under the covers:

!ENTRY org.eclipse.wst.validation 4 0 2008-10-20 09:55:05.783
!MESSAGE
*** ERROR ***: Mon Oct 20 09:55:05 EDT 2008
org.eclipse.core.internal.resources.ResourceException: Marker id
638350 not found.
at
org.eclipse.core.internal.resources.Marker.checkInfo(Marker.java:56)
at
org.eclipse.core.internal.resources.Marker.getAttribute(Marker.java:
97)
at
org.eclipse.wst.validation.internal.TaskListUtility.getValidationTasks(TaskListUtility.java:
331)
at
org.eclipse.wst.validation.internal.TaskListUtility.getValidationTasks(TaskListUtility.java:
390)
at
org.eclipse.wst.validation.internal.TaskListUtility.getValidationTasks(TaskListUtility.java:
443)
at
org.eclipse.wst.validation.internal.TaskListUtility.removeTaskSubset(TaskListUtility.java:
543)
at
org.eclipse.wst.validation.internal.TaskListUtility.removeAllTasks(TaskListUtility.java:
523)
at
org.eclipse.wst.validation.internal.TaskListUtility.removeAllTasks(TaskListUtility.java:
519)
at
org.eclipse.wst.validation.internal.operations.WorkbenchReporter.removeAllMessages(WorkbenchReporter.java:
207)
at
org.eclipse.wst.validation.internal.operations.WorkbenchReporter.removeAllMessages(WorkbenchReporter.java:
672)
at
org.eclipse.jst.j2ee.model.internal.validation.WarValidator.validateInJob(WarValidator.java:
319)
at
org.eclipse.jst.j2ee.internal.web.validation.UIWarValidator.validateInJob(UIWarValidator.java:
111)
at
org.eclipse.wst.validation.internal.operations.ValidatorJob.run(ValidatorJob.java:
75)
at org.eclipse.core.internal.jobs.Worker.run(Worker.java:55)

 

[Legaia]

It's me, again, still having no luck finding anyone else with this problem yet it keeps happening. This time around, my previous solution didn't fix it.

What worked was to close and delete all the projects I wasn't using (delete to Eclipse, doesn't have to be the "real" delete) and restart Eclipse. Finally that fixed it. Even though projects weren't referencing each other, some bad project seemed to screw up the other ones.