Technically speaking, this is not strictly a Unix Revelation. Still, to me it's useful enough to note this down.

We all know Java runs in a virtual machine, and assigns itself in 80% of the cases too little memory to do some real work. Result? Well, this:

Sun gave us the -Xmx flag to increase the heap size (and -Xms to increase the stack size).

This works nicely from the commandline, the next challenge was to do something similar from an R environment. Using RWeka, which in turn depends on rJava, I found myself hitting the limit every time (which defaults to 512 MB).