How to create a heap dump of a running JVM?

Often in order to analyze an out of memory error, you should need a heap dump of your JVM process.

jmap -dump:file=heap.bin <PID>

.... can be used to get a heap dump of an existing JVM.

Reference: http://www.onkarjoshi.com/blog/247/heap-dump-of-a-running-jvm-with-jmap/