Max memory for 64bit Java

Question

What\'s the maximum amount of heap space that one can allocate for java on a 64-bit platform? Is it unlimited?

Answer 1

This probably depends on the system your VM is running in. If you are running a AMD x64 architecture the address space of currently shipped processors uses 48 Bits, not 64. This results in a theoretical maximum of roughly 256 TB. (See http://en.wikipedia.org/wiki/X86-64)

I am not a specialist in VMs, but any modern OS typically will give as much memory as there is physical RAM plus available virtual memory. Probably thats what the VM will pass to your application depending on its configuration.