JMap Heap

Usando o JMap você também consegue analizar o estado to seu heap.

Para isso, basta rodar jmap -heap PID_DA_APLICACAO. O resultado é algo semelhante a isso:

Attaching to process ID 58271, please wait...
Debugger attached successfully.
Server compiler detected.
JVM version is 20.4-b02-402

using parallel threads in the new generation.
using thread-local object allocation.
Concurrent Mark-Sweep GC

Heap Configuration:
   MinHeapFreeRatio = 40
   MaxHeapFreeRatio = 70
   MaxHeapSize      = 268435456 (256.0MB)
   NewSize          = 21757952 (20.75MB)
   MaxNewSize       = 43581440 (41.5625MB)
   OldSize          = 65404928 (62.375MB)
   NewRatio         = 7
   SurvivorRatio    = 8
   PermSize         = 21757952 (20.75MB)
   MaxPermSize      = 85983232 (82.0MB)

Heap Usage:
New Generation (Eden + 1 Survivor Space):
   capacity = 19595264 (18.6875MB)
   used     = 9074128 (8.653762817382812MB)
   free     = 10521136 (10.033737182617188MB)
   46.30776089569398% used
Eden Space:
   capacity = 17432576 (16.625MB)
   used     = 8309072 (7.9241485595703125MB)
   free     = 9123504 (8.700851440429688MB)
   47.66405148613722% used
From Space:
   capacity = 2162688 (2.0625MB)
   used     = 765056 (0.7296142578125MB)
   free     = 1397632 (1.3328857421875MB)
   35.37523674242424% used
To Space:
   capacity = 2162688 (2.0625MB)
   used     = 0 (0.0MB)
   free     = 2162688 (2.0625MB)
   0.0% used
concurrent mark-sweep generation:
   capacity = 8777728 (8.37109375MB)
   used     = 4547440 (4.3367767333984375MB)
   free     = 4230288 (4.0343170166015625MB)
   51.80657227018199% used
Perm Generation:
   capacity = 62521344 (59.625MB)
   used     = 37527360 (35.78887939453125MB)
   free     = 24993984 (23.83612060546875MB)
   60.023277810534594% used

Note que você consegue ver cada um dos espaços de memória e quanto está sendo usado em cada.