How to check if the Java Virtual Machine is 32 or 64 bit

You can try on the command line:

 java -d64 version

If it's not a 64-bit version, you'll get a message that looks like:

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

In general, I recommend to install the 64-bit version of the Java Virtual Machine (JVM).