Although your question is pretty low on detail I would check whether you loose sessions at some point. I have seen the "blank" page issue popping up whenever cookies were involved and somehow got lost. I have never seen partial content though.
If you can reproduce the problem easily use VM remote debugging instead of logging/tracing.
I've seen the situation where a page half renders gets flushed and then an exception is thrown. Try figuring out where the code stops and put in some exception checking.
Can you post code?
Also check whether you encounter an HTTP Connection timeout.
Insufficient buffer size perhaps? I have seen blank pages rendered when pages are too large. Also, if the compiled method exceeds 64K (plenty of print statements) the JVM chokes.
<%@page buffer="32kb" ...
thanx for all the replies, this is what is currently being thought to be the cause of the problem...
There is no escape!!! :0)
I would have bet money on the default 8k page buffer being the problem: seen that one myself.
Also, if you have written your own tags make sure you reset the tag's state. New web containers are aggressive about reusing tag objects whereas you could get away with improper tag implementations in the past because it created new objects for each instance.