This bug was originally marked as duplicate of bug 244142, 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 201504240001)
VM: Java HotSpot(TM) 64-Bit Server VM, 25.31-b07, Java(TM) SE Runtime Environment, 1.8.0_31-b13
OS: Mac OS X
abien: Happened during code completion
Maximum slowness yet reported was 53660 ms, average is 53660
Created attachment 153476 [details]
Already fixed in the current dev build.
*** This bug has been marked as a duplicate of bug 254649 ***