Created attachment 14265 [details]
Stack trace

Not sure what the root cause is; could be a bug in editor, in
java/api, in apisupport/project. If it is reproducible, should be easy
to track down; try e.g.

  -J-Dorg.netbeans.modules.apisupport.project=0

Somebody (and problem is that we do not know who) registered new
classpath to GlobalPathRegistry and editor is trying to parse it.

Tomas, could you please make sure that all support methods for
classpath creation checks its input parameter if possible? Maybe
ClassPath constructor could at least check that all its
PathResourceImplementation does not containg something like
file://.../foo.jar. That might help.

Then I would pass this issue to web/project. Looks most probably as
their issue.

Making P2 just to get this fixed sooner then later.

Can't reproduce currently.

The checking of input parameters will require to iterate the list or
resources, this should net be in the production code. Maybe call it as
assert.

For perf reasons it could be assert. I believe this check will be
valuable.

Checking in api/src/org/netbeans/spi/java/classpath/ClassPathFactory.java;
/cvs/java/api/src/org/netbeans/spi/java/classpath/ClassPathFactory.java,v
 <--  ClassPathFactory.java
new revision: 1.3; previous revision: 1.2
done

I've added the debugging support into ClassPathFactory. The support is
disabled, to enable it uncomment the assert in the createClassPath method.

It seems that the bug is already fixed. I am going to close it. If it
appears again reopen it. The added debugging support may help to find
out the its root case.

Assert is commented out because it is too slow? 

Yes, it is O(n^2)