out of memory error

I'm getting 'out of memory' errors when retrieving the entire contents
of a reasonably large tables. I spent an hour or so trying all the
remedies that showed up via Google search for 'postgresql out of memory'
and nothing seemed to work. The two most often recommended were
increasing Java heap size (I went up to 128m) and
Statement.setFetchSize(1). I saw no significant difference with either
of these.

Is there a way to eliminate these errors? I'm working on an application
that is reading a table and writing it out to a text file after
removing unprintable characters. So my program logic is dead simple:
select * from table
while ( rs.next() )
process and write;

My driver is postgresql-8.1-407.jdbc3.jar

Thanks,
-=bill