Heap dump, java visualVM

http://www.quizful.net/post/java-memory-leak-visualvm

https://habrahabr.ru/company/luxoft/blog/146988/

https://shipilev.net/blog/archive/visualvm/

https://habrahabr.ru/post/253683/

http://docs.oracle.com/javase/6/docs/technotes/tools/share/jhat.html