Java programing for 64 bit JVM

Question

Few Questions :):

How to identify what JVM is currently installed ? (64 bit / 32 bit)

Do I need to do some considerations while programming for 64 bit JVM target Platform ?

Can my Java code work on 32 bit as well as 64 bit JVM ?

How to run my Java App on 64 bit JVM ?

How to identify what JVM is being used for my Java App ?

Answer 1

Normally a 64 bit jvm will identify itself as such.

32/64 bit Considerations I have seen:

1. address space - if you're not expecting to address more that 1.3Gb of memory then you won't see a difference
2. native libraries - if you're loading any JNI libs, then they will need to match your VM architecture. For example, don't try loading 32-bit native libraries from a 64-bit vm (without -d32 type of flags)

Yes, the same code will run on both JVMs.

System Property "sun.arch.data.model" has the 32/64 flag I think.

There's some helpful info here: http://www.oracle.com/technetwork/java/hotspotfaq-138619.html