How to get the size of a process?

I am dealing with a Java application, which creates multiple versions of a named window.

The named windows give a result of 0 (zero)  when called

Requesting delivers the expected results, but not the size as posted in the fifth column of the task manager list.

The PID handle is easy to get with WinGetHandle("xyzabc - era", ""), but I cannot find a way to get the matching size.

Does anyone know a way?