Jmap can't connect to make a dump

Question

We have an open beta of an app which occasionally causes the heapspace to overflow. The JVM reacts by going on a permanent vacation.

To analyze this I would like to

Answer 1

When none of these work or if you don't want to change sensitive OS flags such as ptrace_scope:

Either you can use jconsole/jvisualvm to trigger heap dumps or run any JMX client directly from console as follows as you are doing it locally on the machine that needs the dump and so is faster:

echo 'jmx_invoke -m com.sun.management:type=HotSpotDiagnostic dumpHeap heapdump-20160309.hprof false' | java -jar jmxsh.jar -h $LOCALHOST_OR_IP -p $JMX_PORT

I used the wget https://github.com/davr/jmxsh/raw/master/jmxsh.jar for this example.