NPE in PooledConnction event notification handling if a null listener is added

• Key: DERBY-3307
• Type: Bug
• Status: Closed
• Resolution: Fixed
• Priority: Minor
• Assignee: Knut Anders Hatlen
• Reporter: Kristian Waagan
• Component/s: JDBC
• Affects Version/s: 10.3.2.1, 10.4.1.3
• Fix Version/s: 10.4.2.0, 10.5.1.1

Description

If a null reference is passed in to one of the ClientPooledConnection.addXEventListener, a NPE will be thrown if an event occurs.
I will attach a simple repro as a patch to the test jdbc4.StatementEventsTests. I believe the situation is the same for connection event listeners.

I have found no information in the specs regarding null listeners, but I assume it would be okay to ignore them.

Comments

[Kristian Waagan]

'derby-3307-1a-test_repro.diff' can be used as a repro for this issue. It adds another test to jdbc4.StatementEventsTests.

[Kristian Waagan]

Note that the existing repro ('derby-3307-1a-test_repro.diff') only tests the statement event listener case, which has already been fixed (see DERBY-3695).
Another repro / test should be written for a connection event listener.

[Knut Anders Hatlen]

> I have found no information in the specs regarding null listeners, but I assume it would be okay to ignore them.

That's at least what the embedded driver does. And it would be consistent with how listeners work in the Swing/AWT world.

[Knut Anders Hatlen]

The attached patch adds a null check in ClientPooledConnection.addConnectionEventListener() and a regression test in J2EEDataSourceTest.

[Knut Anders Hatlen]

Committed revision 666040.

[Knut Anders Hatlen]

Merged to 10.4 and committed revision 666094.

[Kristian Waagan]

I verified the fix in trunk by running the repro after removing the code change in CPC. It fails with the code removed, and succeeds with the code in place.

Thank you Knut Anders!