garbage collection

I have an jython/visad program which produces 4 windows with 3 d
displays. After preparing the displays, I would like to read new
data in and recreate the windows.

I have set this up to close all the windows and then begin reading
in the new data again from the server.  I presumed that the garbage
collector would release the resources for the old run.

In the second set of displays the response is very slow and the
memory footprint is larger.  

Is there something special about running the garbage collector with
jython or visad?  How can I releaxe the memory used by arrays in
jython?

Thanks

G. Garrett Campbell Ph. D.
Cooperative Institute for Research in the Atmosphere
Colorado State University
Ft. Collins, CO, USA
970 491 8497
campbell@xxxxxxxxxxxxxxxxxx