Parsing large XML files with a SAX parser can definitely be a memory hog
and consume large amount of heap. You need to understand much better,
when you are running short of memory, and based on that you can start
with both heap analysis and more testing. And regarding performance:
Yes, you should have an amount of free RAM on system which is not
consumed by Java heap, and which can be used as cache. But only a
profiler run (or a good observation on an OS level) can tell if this is
really a bottl...