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Restrictions for J/Link-ed Programs?

• To: mathgroup at smc.vnet.net
• Subject: [mg100887] Restrictions for J/Link-ed Programs?
• From: Christian Staudt <christian.staudt at ira.uka.de>
• Date: Wed, 17 Jun 2009 04:38:04 -0400 (EDT)

Hi MathGroup,

I would like to use Mathematica with J/Link as a frontend and plotting  
environment for a computing-intensive benchmark written in Java.  
Unfortunately, I ran into the following two (related?) problems:

a) As soon as the memory footprint of the Java process reaches about  
260 MB (on my Macbook) or about 320 MB (on my Linux machine), it  
grinds to a halt. Apparently, the memory footprint is not allowed to  
increase any further, so the garbage collector goes out of its way to  
free memory - but will eventually fail with a "GC overhead exceeded"  
exception.

This happens only if the program is called with J/Link. Called from  
the command line, it runs normally since it is allowed to use more  
memory. I tried to pass e.g.  "java -Xmx2000m ..." as an Argument to  
ReinstallJava[CommandLine->...], but Mathematica seems to ignore or  
override the -Xmx option.

b) The benchmark uses the linear program solver Cplex, which needs to  
communicate with a license token server in order to work. Again, it  
runs just fine from the command line, but not with J/Link. The  
communication with the license server fails with a timeout.

My guess is that Mathematica puts restrictions on the linked program  
for security reasons or similar - affecting memory usage (a) and  
network communication (b). I could not find information on this on the  
web.

Is my guess correct? If yes, how can these restrictions be removed?

If I cannot solve this I have to do a laborious workaround, calling  
the Java program via Run[] ... so quick help would be very much  
appreciated. Thank you!

Greetings,
Christian