Can i use more heap than 32 GB with compressed oops

Question

I could understand that with compressed oops , we can only use 32 GB of RAM. Is there someway i can use more than that like by allocating 2 heap or something ?

Thank

Answer 1

What exactly is the nature of the data?

The way to do this might be to store the data off the Java heap. You can do this by getting hold of some off-heap memory, typically using a direct ByteBuffer, and then storing data in it in the form of bytes. This has various advantages; the objects can be stored very compactly, you don't need to have a huge heap, and the objects won't be swept by the garbage collector. The disadvantage is the complexity, and the risk of memory leaks.

There are libraries which can help you do this, including:

• http://code.google.com/p/vanilla-java/wiki/HugeCollections
• http://directmemory.apache.org/