This bug was originally marked as duplicate of bug 171690, that is already resolved. This bug is still valid, so this seems to be another bug, but it might be related.
Build: NetBeans IDE Dev (Build nbms-and-javadoc-4313-on-091116)
VM: Java HotSpot(TM) 64-Bit Server VM, 14.3-b01, Java(TM) SE Runtime Environment, 1.6.0_17-b04
OS: Linux, 2.6.31-12-generic, amd64
geoffw: open maven project for first time
Maximum slowness yet reported was 18368 ms, average is 18368
Created attachment 91492 [details]
the closing operation is waiting at many other tasks being performed in other threads (MavenFileOwnerQuery, OpenProjects, GlobalClassPath)
so the action should not execute in AWT thread I believe, reassigning to project/ui
Created attachment 91911 [details]
Created attachment 93147 [details]
trying to open, and then gave up, and tried to close a large maven project. in general netbeans can be painfully slow - still the best IDE though!
Created attachment 94614 [details]
Closing a lot of maven projects
Most issues should be resolved by a simpler FileOwnerQuery. At least one snapshot seems to be unrelated - java.source.classpath.CacheClassPath.propertyChange doing heavy work in a listener callback - but is probably filed separately anyway.
BTW I see nothing from NB 6.9.
*** This bug has been marked as a duplicate of bug 186024 ***