Why don't sun provide Object.getInternalAdress()?

Question

Why is it so hard for sun to add the method getInternalAdress()-> long/java.math.BigInteger to Object (which gives the internal adress of the object).
In documentation for Object.hashCode() it is stated: "This is typically implemented by converting the internal address of the object into an integer, but this implementation technique is not required by the JavaTM programming language.)"
And when you call Object.toString() that String has the internal adress in it.
So why cannot sun simply give access to the internal adress? It's obviously there! I can understand it has to do with platform-portability since for an example an int-adress would only work for 32-bit platform. But won't long or at least java.math.BigInteger be platform-portable?
Gil

Answer 1

Why is it so hard for sun to add the method
getInternalAdress()-> long/java.math.BigInteger to
Object (which gives the internal adress of the
object).For one reason, there would be no point to it. Java makes no guarantees about the memory layout of an object in memory or the size of objects, so what would you do with an address?
For another reason, objects move around in some JVMs (for example, when the heap is compacted), and in other JVMs objects stay still. If Sun provided a way to get the address of an object, programmers who developer with a JVM where objects stay still might assume objects stay still in all JVMs and write bad code.
For yet another reason, you cannot access arbitrary memory in Java, so there's nothing you could possibly do with an address anyway.
Can you give any reason why you might want the address of an object, keeping in mind the above points?