customer's email:

We use Java version:
>java -fullversion:
java full version "1.3.0-C"

>java -version:
java version "1.3.0"
Java(TM) 2 Runtime Environment, Standard Edition (build 1.3.0-C)
Java HotSpot(TM) Client VM (build 1.3.0-C, mixed mode)
 
a) System resources under WinNT 4.0 SP5

Watching the system resources, when opening, closing and destroying Java
windows does produce the following behavior: Any action taken on Java
windows will consume a specific amount of memory. The Java VM increases
continuously. Even a System.gc(); does not force the VM to free up memory.
However, minimizing the Java windows into the system taskbar actually does
free up almost any resource, which was allocated for managing the windows.
Please explain this behavior and tell us, if there is a way to force the VM
to free up system resources no longer used.

The enclosed example window.jar does demonstrates this behavior:
- start it by running "java -cp window.jar Control"
- pressing "Create new Windows" creates 100 new windows. Spreading them over
the desktop allocates a lot of resources.
- pressing "Close all Windows" closes them. Again, additional resources are
allocated.
- repeating the last 2 steps always consumes a little bit more resources.
- closing all windows and minimizing the control panel frees up almost any
resources.

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I can verify this under Solaris 8 too.
see attached log file from sdtprocess. ram and swap usage grows continuously when opening and closing windows.