Tim Ellison wrote:
Hi Kevin,
Kevin Zhou wrote:
I think this defect may be a thread-safe problem.
I read HARMONY's PropertyChangeSupport code and found that:
It employs ArrayList to store the property change listeners which is not
thread-safe.
This defect occurs in a private doFirePropertyChange method.
This method may asynchronously use the list of PropertyChangeListener, which
contains a null value when modification (add or remove) of the list has not
finished.
Yes, I put in some trace code and there is a null stored in the
globalListeners list which causes the NPE.
However, I don't see where that null could have been stored. Can you
suggest what part of the code has stored the null in there? Every add
to the list first checks for null. I'll take a look and see if I can
catch it in the test.
I won't apply your 'check-for-null' patch since I think that just masks
the underlying problem.
Regards,
Tim
Hi Tim,
This patch doesn't only check-for-null.
It also changes the private doFirePropertyChange method to synchronized
method. This may resolve the asynchronous operation on globalListeners list.
I will try to find what part of the code has stored the null.
Due to license cares, I think it difficult to find the setting-null code
which may be inside SwingSet2.jar.
Will manage to handle this.
Kevin Zhou
