Do the overriding methods must have the same return type(or sub-type)?

 Q.1  Do the overriding methods must have the same return type(or sub-type)?

·         Form java 5.0 onward it is possible to have different return types for an overriding method in the child class. but child return type should be sub-type or parents return type.

§  This phenomenon is known as | convenient return type.

Example:-

class   Test   {

object   show()  {
System.out.println(“one”);

return null;

}

}

class  Test1   extends   Test    {

String show()     {

System.out.println(“one”);

return null;

}

public static void main(String    args[])    {

Test  t  =  new Test();

t.show();

Test1  t  =  new Test1();

T1.show();

}
}

Ø  Before JDK  5.0 it was not possible to vary a  method by changing the return type.

Ø  Java  5.0 onward it is possible to have different return types for an overloading method in child class but child return type should be a subtype of a parents return type overriding method become variant with respect to return type  .so this is known as correct return type.

Q.2  Overriding and  Access-modifier?

Ø  The access modifier for an overriding method can allow more but not less, access than the overridden method.

Example:-    a protected instances method in the superclass can be made public but not private in the subclass doing so will generate a compile-time error.

class   Test   {

protected/default/ public void   show()  {
System.out.println(“one”);

}

}

class  Test1   extends   Test    {

public void show()     {

System.out.println(“one”);

}

public static void main(String    args[])    {

Test  t  =  new Test();

t.show();

Test1  t  =  new Test1();

T1.show();

}
}