You can use following property to get processor architecture:
System.getProperty("sun.cpu.isalist");
It returns "amd64" as i am using Intel's 64 bit processor and Intel 64 bit uses amd architecture.
If you need OS architecture value you can use this property "os.arch"
And if you need any other property then this might help you. I wrote following snippet to get all system properties:
public static void main(String[] args) {
Properties props = System.getProperties();
Enumeration