[POOL-411] NPE when deregistering key at end of borrow

• Type: Task
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Affects Version/s: 2.11.1
• Fix Version/s: 2.12.0
• Assignee: Unassigned
• Reporter: Richard Eckart de Castilho
• Created: 19/Feb/23 09:53
• Updated: 01/Oct/23 22:46
• Resolved: 01/Aug/23 02:37

Description

There is a potential for an NPE happening in the finally block of borrowObject:

Caused by: java.lang.NullPointerException: Cannot invoke "org.apache.commons.pool2.impl.GenericKeyedObjectPool$ObjectDeque.getNumInterested()" because "objectDeque" is null
	at org.apache.commons.pool2.impl.GenericKeyedObjectPool.deregister(GenericKeyedObjectPool.java:821)
	at org.apache.commons.pool2.impl.GenericKeyedObjectPool.borrowObject(GenericKeyedObjectPool.java:507)
	at org.apache.commons.pool2.impl.GenericKeyedObjectPool.borrowObject(GenericKeyedObjectPool.java:350) 

From reading the code, it seems this could happen e.g. if a pool is concurrently cleared while a borrow is in progress.

Not sure what a proper solution here would be. Maybe deregister should silently do nothing if poolMap.get(k) returns null?

Issue Links

• links to: GitHub Pull Request #231