JVM 64-bit OutOfMemory / Compressed references

If you are running on 64-bit OS and JRockit JVM 64-bit has the heap < 4GB in size and you experience OutOfMemory errors, try disabling compressed references by using the following option in your scripts:

-XXcompressedRefs[=[true|1|false|0]]

or

-XXcompressedRefs:parameter=value

where 1/true stands for enabling the option.

You can also use the following format, when using different heap sizes:

-XXcompressedRefs:enable=true

or

-XXcompressedRefs:size=4GB for Xmx <=2g
-XXcompressedRefs:size=32GB for Xmx <=25g
-XXcompressedRefs:size=64GB for Xmx <=57g

What compressed references does, it limits all pointers (to classes, objects, threads) stored on the heap to 32bits, hence less usage of the heap.