What is the mechanism to choose which overloaded method

in the example
public class A
  public void m(Object o)
    System.out.println("Object");
  public void m(Integer i)
    System.out.println("Integer");
  public void m(Double d)
    System.out.println("Double");
  public static void main(String[] args)
    A a = new A();
    a.m(null);
}Which method is called and why... What is the mechanism by which the compiler decides on the method to call...
Not significant since I'd shoot anyone writing their code like this... But hey curiosity killed the cat...
Talden

Yep, this example gives the following error (under 1.4):
Test.java [26:1] reference to m is ambiguous, both method m(java.lang.Integer) in Test and method m(java.lang.Double) in Test match
Casting null to either Object, Double or Integer should work fine. I think what your getting at is something I've hit myself - what if I got an object from some method as a return type - why can't I call "m" on it and have java determine which method to call? I think this might be introduced in 1.5 with the new generics stuff, but I'm not sure.....

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