Its a overLoading .because overriding have two diff class 
and return type also same

but overloading have one class,and it have same method name 
and diff signature.

Niether overloading nor ovverriding ,this question has errors

Overloading---->different method
signatures(order,type,number different)
Ovveriding signature same but subclass can implement this method


So ??????????????.

it is not overloading bcos different return types does not mean overloading.
n 4 overriding inheritance should b used between 2 classes.
so it is neither overriding nor overloading.

If both signature are same, i.e parameters
and if the method has co-variant return type 
which means  return type of int in one method and 
return type of long in another method.
Consider safely as the method is overloaded.

if otherwise it's neither overloaded or overrided
just an another method in the class.

See overloading has nothing to do with Covariant Return
types ,in fact overloading dosent take into consideration
the return types.

But in case of ovveriding u can provide Covariant return type

say for example

class A {
 protected A getModel(){
   return this;
  }
}
class B extends A{

  public B getModel(){

     return this
  }
 }
and there are many other examples of 
covariant return types like this.

Since B is A(IS-A RelationShip)
 so the return type can be a subclas of the super class

It is not overloading because overloading must have different parameters, no matter what ever may be the return type is.
And  for overriding inheritance should be used between 2 classes.
so it is neither overriding nor overloading.

It just show compilation error as method is already defined in 
same class

public class sample
{
	public void displayValue (int a, int b)
	{
		System.out.println("a = "+a +" b = "+b);
	}

	public int displayValue (int a, int b)
	{
		System.out.println("a+b:"+(a+b));
		return (a+b);
	}

	public static void main(String[] args) 
	{
		sample t = new sample();
		t.displayValue(10,10);
		int x = t.displayValue(20,30);
	}
}



Output:

D:\Prg>javac sample.java
sample.java:8: displayValue(int,int) is already defined in
sample
        public int displayValue (int a, int b)
                   ^
sample.java:18: incompatible types
found   : void
required: int
                int x = t.displayValue(20,30);
                                      ^
2 errors