Memory leak in AbstractCorrelatingMessageHandler #3794
Description
In what version(s) of Spring Integration are you seeing this issue?
SI core 5.x
Describe the bug
Hard references to completed and released MessageGroup instances stored memory by AbstractCorrelatingMessageHandler
Additional details
Please see the following discussion: 2f0b377#r73229543, also note this is effectively a sibling of https://jira.spring.io/browse/INT-3999, the fix for which was never applied to the empty group removal logic.