Possible Duplicate:
Maximum Java heap size of a 32-bit JVM on a 64-bit OS
We have a 64 bit Linux server running the 32 bit JVM. We do not want to upgrade to 64 bit JVM for various internal reasons. What is the maximum -xmx value that would work assuming my OS can use way more than a 32 bit program can use?
Is it exactly 4096 or is there some padding where it has to be lower?
3788.8 MB is the max heap size for a 32-bit JVM on a 64-bit Linux.
Source: http://pauldone.blogspot.com/2008/08/is-jvms-maximum-heap-size-really-17-gb.html
(For older Java so might actually be more or less for Java 6)