[jdom-interest] JDOM Stack vs. Frame Performance?

McFarland, Todd Todd.McFarland at fmr.com
Thu Dec 21 05:03:36 PST 2000


I have a question that is probably a Java question in general.

I'm noticing poor performance on objects (Including JDOM) I'm trying to
create on the stack
as opposed to private variables (Frame).

For example - if I declare a JDOM doc locally to a function and load a large
XML file, and then
pass its reference to another function and recurse through its nodes.
Performance is relatively terrible in the Servlet.

I then tried two simple changes and I was really surprised:
1.  I moved the declaration (only) to a private variable.  Performance was
still awful because I was still
	passing the private variable as references to other functions (just
testing!).
2.  I eliminated the unnecessary object reference from the call to the other
functions - performance was excellent.

I'm noticing this kind of behavior on other objects as well.

Please note - I'm actually a C++/VB guy so I'm not a real Java expert.  To
me, it looks like a memory
allocation issue.  Can anyone comment?

Thanks,
- Todd




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