How to find java heap memory usage ?
jmap -heap 26442 Attaching to process ID 26442, please wait... Debugger attached successfully. Server compiler detected. JVM version is 8.1.045 9.0.4+011 using thread-local object allocation. Garbage-First (G1) GC with 8 thread(s) Heap Configuration: MinHeapFreeRatio = 40 MaxHeapFreeRatio = 70 MaxHeapSize = 27262976000 (26000.0MB) NewSize = 5452592 (5.1999969482421875MB) MaxNewSize = 16357785600 (15600.0MB) OldSize = 5452592 (5.1999969482421875MB) ...