How to check heap usage of a running JVM from the command line?

Question

Can I check heap usage of a running JVM from the commandline, I mean the actual usage rather than the max amount allocated with Xmx.

I need it to be commandline beca

Answer 1

If you start execution with gc logging turned on you get the info on file. Otherwise 'jmap -heap ' will give you what you want. See the jmap doc page for more.

Please note that jmap should not be used in a production environment unless absolutely needed as the tool halts the application to be able to determine actual heap usage. Usually this is not desired in a production environment.