Java EE (Java Enterprise Edition) General Discussion

In my application I write a byte array (the content of a file) to a ServletOutputStream. To do this, I user writeand at the end, the flush()-command.
However, my application is memory-critical, so I do not want to use many memory if the file I want to write to is very big.
Does anybody know if and when yes how I can limit the buffer the OutputStream writes to before flushing?
Does anybody know what internal datastructure is used and how the data is be organised?

Thank you very much for help

Volker