<Swing Dev> Patch for NPE at javax.swing.plaf.basic.BasicTreeUI$Actions.page:4470

[Jaroslav Tulach]

Dear Swing maintainers,
my name is Jaroslav Tulach and I am maintaining NetBeans explorer - a 
component that is using JTree heavily.

>From time to time I receive a user report with a NPE from Swing where little 
or even no NetBeans code involved. Just today I got
http://netbeans.org/bugzilla/show_bug.cgi?id=222081
We have about 35 other ones (which is not that much given the fact we have 
million of users), but still...

According to
http://statistics.netbeans.org/exceptions/exception.do?id=628832
the report comes from jdk7u9-b05. The source code is here
http://hg.openjdk.java.net/jdk7u/jdk7u/jdk/file/jdk7u9-
b05/src/share/classes/javax/swing/plaf/basic/BasicTreeUI.java
and thus it looks like the call on line 4468 to

ui.getPathBounds(tree, newPath);

can return null (under some rare and unknown circumstances). 

I can close the bug #222081 as "worksforme", but it is clear that such error 
happens from time to time and we don't want our users to face errors. A 
simple:

4469 if (newRect == null) return;

would do the trick. One question remains: if I try to donate such patch, will 
you accept it?
-jt