How do I detect which kind of JRE is installed — 32bit vs. 64bit

Question

During installation with an NSIS installer, I need to check which JRE (32bit vs 64bit) is installed on a system. I already know that I can check a system property \"su

Answer 1

import sun.misc.*;

import java.lang.reflect.*;

public class UnsafeTest {
  public static void main(String[] args) throws NoSuchFieldException, IllegalAccessException {
    Field unsafeField = Unsafe.class.getDeclaredField("theUnsafe");
    unsafeField.setAccessible(true);
    Unsafe unsafe = (Unsafe) unsafeField.get(null);
    System.out.println(unsafe.addressSize());
  }
}