How can I tell if I’m running in 64-bit JVM or 32-bit JVM (from within a program)?

Question :

How can I tell if the JVM in which my application runs is 32 bit or 64-bit? Specifically, what functions or properties I can used to detect this within the program?

Solution:

For certain versions of Java, you can check the bitness of the JVM from the command line with the flags -d32 and -d64.

$ java -help
...
    -d32          use a 32-bit data model if available
    -d64          use a 64-bit data model if available

To check for a 64-bit JVM, run:

$ java -d64 -version

If it’s not a 64-bit JVM, you’ll get this:

Error: This Java instance does not support a 64-bit JVM.
Please install the desired version.

Similarly, to check for a 32-bit JVM, run:

$ java -d32 -version

If it’s not a 32-bit JVM, you’ll get this:

Error: This Java instance does not support a 32-bit JVM.
Please install the desired version.

Posted from: https://stackoverflow.com/questions/2062020/how-can-i-tell-if-im-running-in-64-bit-jvm-or-32-bit-jvm-from-within-a-program