Memory usage information of a Java Program

Question

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How to monitor Java memory usage?

My Java Program loads hash map with large number of values from the database. Is there any way through which I may know that how much memory each of my hash map is using during the program is running.

I am aware that it may not be a constant value but any near approximation will also do. Or maybe how much memory each of the hash map consumes while it is loaded with data from Sql Server.

Thanks

You could come to a rough esimate if you execute the program in an IDE and use its profiling features. I.e. you could use Eclipse + TPTP. — home, Jul 24 '11 at 09:12
Yes I am using eclipse IDE. TPTP - can you clarify this a little more? Thanks — JavaBits, Jul 24 '11 at 09:25
@JavaBits: ...and as far as I can see the answer in that question will work for you. Determine memory before and after you fill the hash map.... — Mitch Wheat, Jul 24 '11 at 09:30
BTW, this is *not* a duplicate of the other question. This question asks for memory usage of a particular object (tree) — Bohemian, Jul 24 '11 at 09:46
@Bohemian : which can be ascertained in the same way that the duplicate describes. — Mitch Wheat, Jul 24 '11 at 11:45

score 2 · Accepted Answer · answered Jul 24 '11 at 09:41

2

If you want to estimate the size of specific data structures at runtime, Heinz Kabutz's newsletter describes how to do this using instrumentation: Instrumentation Memory Counter.

answered Jul 24 '11 at 09:41

McDowell

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score 0 · Answer 2 · answered Jul 24 '11 at 09:21

0

If you want an estimate use a profiler like VisualVM or YourKit.

You could estimate how large an entry key/value is and multiply it by the number of entries.

answered Jul 24 '11 at 09:21

Peter Lawrey

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Memory usage information of a Java Program

2 Answers2