#2 How can i increase max heap memory size

[Anonymous]

I want to increase the max heap memory size of the the
virtual machine running jsh shell.
Then i have already modified the script jsh.sh adding
the following options to the command line ruuning java... :
-Xmx512m -Xms500m -Xss500m

But after about 80 mb of java heap used i obtain the
message:
java.lang.out.OutOfMemory

Is there any other command line to increase java heap
size ?

Thanks for any suggestions