You can use jmap to get a dump of any process running, assuming you know the pid.
Use Task Manager or Resource Monitor to get the pid. Then
jmap -dump:format=b,file=heap.hprof <pid>
to get the heap for that process.
For systems where bash and pgrep are installed and a single Java process is running, try:
jmap -dump:format=b,file=heap.hprof $(pgrep java)