Java : how to check current Perm / PermGen Size?

Question

Yesterday when I was running the WebLogic Application Server 11g installer, I encountered a OutOfMemory error, so I Googled for the answer:

java -Xms256m -Xmx512         


        

Answer 1

Another way to get PermGen information is:

kill -3 JAVA_PID

It gets thread dump and memory information (including PermGen). Example output:

PSPermGen       total 68864K, used 68808K [0x000000009c600000, 0x00000000a0940000, 0x00000000a1800000)

For some reason jinfo did not work when I needed it. It returned:

Unable to open socket file: target process not responding or HotSpot VM not loaded

There are few possible causes of the above and one of them may be explicit declaration of the java.io.tmpdir as described at https://www.permeance.com.au/web/terry.mueller/home/-/blogs/unable-to-open-socket-file-target-process-not-responding-or-hotspot-vm-not-loaded