On 11/15/2012 7:58 PM, Jaroslav Tulach wrote:
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?
The ui.getPathBounds(tree, newPath) method definitely can return
null so it needs to have this check.
However, such fix can mask the real issue, for example, in the
treeState.getBounds() method where the treeState can be instance of
FixedHeightLayoutCache or VariableHeightLayoutCache class.
If it is possible, could you send a code snippet that shows how
NetBeans uses JTree? May be it can give a hint what can be wrong in this
case.
Thanks,
Alexandr.
-jt
