To which class, object is refering to?

[Madhu Desai]

Hi

below is my sample program

class SuperClass {
	public void tellMe() {
		System.out.println ("I am in Super Class");
	}
}
class SubClass extends SuperClass {
	public void tellMe() {
		System.out.println ("I am in Sub Class");
	}
}
public class Example {
	public static void main (String[] args) {
    	SuperClass sc = new SubClass();
    	sc.tellMe(); //prints "I am in Sub Class"
    	System.out.println (sc.getClass()); //Result will be "class SubClass"
    }
}

From line no 13, i can clearly make out that "sc" is of SubClass object which refers to SuperClass reference.
I was able to display that in line no 15, with sc.getClass(), which shows to which class the object belongs.

Is there any way i can display to which class "sc" (in this case) is referencing to?

[Devaka Cooray]

java.lang.Class has a method getSuperclass(), which can be used to get the Class object which represents the super class of it. You can also use the getGenericSuperclass() which returns a Type object that representing the direct super class of the given object.

System.out.println (sc.getClass().getSuperclass());

This is not available in SCJP objectives. For further discussion of this, or for any other reflection-based questions, please post in an appropriate forum.

Devaka

[Ankit Garg]

But still you cannot find the exact class with which the reference was declared. This is because there can be multiple level of inheritance like in your example, you can declare sc to be of type Object...

[Devaka Cooray]

Ankit Garg wrote:But still you cannot find the exact class with which the reference was declared. This is because there can be multiple level of inheritance like in your example, you can declare sc to be of type Object...

I don't think there is a way to get the exact reference type at runtime.

[Madhu Desai]

Devaka Cooray wrote:This is not available in SCJP objectives. For further discussion of this, or for any other reflection-based questions, please post in an appropriate forum.

Point noted..

But this was definitely related to SCJP (not of course about .getSuperclass())

i just wanted to know a better way to figure it out to which class object is referencing (line 14 and 17), like in the example:
K&B :Chapter 2 - Self test - Question 8 (Modified)

class Dog {
	public void bark() {System.out.println ("woof ");}
}
class Hound extends Dog {
	public void sniff() {System.out.println ("sniff ");}
	public void bark() {System.out.println ("howl ");}
}
public class DogShow {
	public static void main (String[] args) {
    	new DogShow().go();
    }
    void go() {
    	
    	new Hound().bark();
    	System.out.println ((new Hound()).getClass());
    	
    	((Dog) new Hound()).bark();
    	System.out.println (((Dog) new Hound()).getClass().getSuperclass());
    	
    	//((Dog) new Hound()).sniff();
    }
}    

I wanted a way to confirm myself that what i thought is reference class is indeed true.

Thanks very much for your help

[Devaka Cooray]

Madhu Desai wrote:I wanted a way to confirm myself that what i thought is reference class is indeed true.

That's really good

[Ankit Garg]

Devaka Cooray wrote:

Ankit Garg wrote:But still you cannot find the exact class with which the reference was declared. This is because there can be multiple level of inheritance like in your example, you can declare sc to be of type Object...

I don't think there is a way to get the exact reference type at runtime.

That's what I was also trying to say