Heap dump shows memory accumulation in one instance of org.jgroups.protocols.pbcast.NAKACK

Issue

• We are analysing a heap dump and we have a problem:

One instance of "org.jgroups.protocols.pbcast.NAKACK" loaded by "org.jboss.classloader.spi.base.BaseClassLoader @ 0x2aaacfe84578" occupies 609,198,944 (38.19%) bytes. The memory is accumulated in one instance of "java.util.concurrent.ConcurrentHashMap$Segment[]" loaded by "<system class loader>".

Keywords
org.jboss.classloader.spi.base.BaseClassLoader @ 0x2aaacfe84578
org.jgroups.protocols.pbcast.NAKACK
java.util.concurrent.ConcurrentHashMap$Segment[]

Can you see where the problem is ?

• Heap dump shows org.jgroups.stack.NakReceiverWindow occupying a high percentage of the heap

Class Name                                                          | Shallow Heap | Retained Heap
---------------------------------------------------------------------------------------------------
org.jgroups.stack.NakReceiverWindow @ 0xccdc60b8                    |           88 |   465,927,320
|- listener org.jgroups.protocols.pbcast.NAKACK @ 0xccdc1c38        |          232 |   465,966,160
|  |- xmit_table java.util.concurrent.ConcurrentHashMap @ 0xccdc5d90|           48 |   465,932,648
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