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java.lang.OutOfMemoryError: Java heap space when doing a JDBC read from Oracle

Answer 1

+2 A:

You're editing the correct setting (although it's -Xmx, not -xmx), but it sounds like you need to increase it further, e.g.

-Xmx256m

As far as the 64 bit thing is concerned, you'll find that a 64bit JVM uses up heap much faster than a 32bit JVM (which makes sense, the pointers are twice the size), so a 64bit JVM needs more heap anyway.

skaffman 2010-06-21 20:46:50

-XX:+UseCompressedOops helps to reduce the heap size on 64-bit JVM's, with a slight performance penalty incurred.

rhu 2010-06-21 23:05:46

+XX:+UseCompressedOops did the trick!

Keith 2010-06-22 21:27:40

Answer 2

+1 A:

Can't out of memory also come form a lack of PermGen? More to memory than just heap

-XX:MaxPermSize=128m

bwawok 2010-06-21 22:46:16

It can. But if it does' the OOME's error message will *tell you* that you are out of permgen space. If it doesn't tell you, you would be wise *not* to twiddle that particular knob! Besides, permgen space is *unlikely* to be relevant to reading a JDBC resultset.

Stephen C 2010-06-21 23:31:00

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java.lang.OutOfMemoryError: Java heap space when doing a JDBC read from Oracle

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