jmap a JVM from a different user

Hello,
how can I get a jmap Heap from different users.

If the user1 has the process and the command       jmap -heap PID      it worked fine.

But if I try the command with another user like user2 there is the message:


Error attaching to process: sun.jvm.hotspot.debugger.DebuggerException: Can't attach to the process


Can I get the Heapsize of a JVM from other users?

Thanks for your ansers.

Regrads,

Tobi