Customer is getting error:
java.lang.ClassNotFoundException: com.sun.management.HotSpotDiagnosticMXBean when using the SpaceProxyConfigurer running on Java 8 on an IBM J9 VM within WebSphere.
I can see in our open source code repository where the HotSpotDiagnosticMXBean was added.
(It also can be found in com/gigaspaces/internal/dump/heap/HeapDumpProcessor.java)
It seems this change was added prior to 15.5 in JIRA GS-14028.
According to this documentation I found on IBM's website, they have their own method for generating a heap dump that doesn't use HotSpotDiagnosticMXBean.
They are getting the error when they instantiate the gigaspace proxy.