#120577:NullPointerException at org.netbeans.modules.refactoring.java.RetoucheUtils.getOverridingMethods

http://netbeans.org/bugzilla/show_bug.cgi?id=120577
http://hg.netbeans.org/main-silver?cmd=changeset;node=c5b9690980f6
http://hg.netbeans.org/main-silver?cmd=changeset;node=f9908b4fb46a

The NPE is thrown during refactoring when the index returns element handle which cannot be resolved.
The handle cannot be resolve either because the source has been deleted (fixed in changeset c5b9690980f6)
or the index returned wrong reference (fixed in changeset f9908b4fb46a)

Fix: Checking existence of source file. Fixing index to delete temporary records created when the class name is changed.

Impact: Refactoring throws NPE during rename of method.

Risk: None I'm aware of.