get java version of a running java process

Question

I can use jps to list running java processes and use jstack -l process_id to get a stack information of a running java process. I want to know this process runs on which java version. Is there a way to do it? I don't have to use jstack tool. thanks.

jstack -l 23819 2014-11-12 12:36:11 Full thread dump OpenJDK 64-Bit Server VM (23.25-b01 mixed mode):

"Attach Listener" daemon prio=10 tid=0x000000000272f800 nid=0x614b waiting on condition [0x0000000000000000] java.lang.Thread.State: RUNNABLE

Locked ownable synchronizers: - None

Answer 1

You can do it via jcmd, like this:

jcmd process_id VM.version

Answer 2

In Linux you could do

sudo strings /proc/<java_pid>/smaps |grep jre

which will produce something similar to

7f8ff82ac000-7f8ff82ad000 r-xp 00000000 fd:00 252363860 /usr/java/jdk1.8.0_141/jre/lib/amd64/libjaas_unix.so

From this you can clearly see what JDK version it's using.