HeapDumper performs merge on the current thread if the current thread is AttachListenerThread, otherwise merge is performed on VMThread.
In other heap dump scenarios:
- JMX (HotSpotDiagnosticMXBean);
- -XX:+HeapDumpBeforeFullGC/ -XX:+HeapDumpAfterFullGC;
- -XX:+HeapDumpOnOutOfMemoryError
merge should be performed on the current thread too.