Subclass Method Changes Return Type to a Different Class in Interface In Java

Write a Java program to demonstrate method overriding with a subclass that overrides a method from an interface and changes the return type to a different class

The interface MyInterface with a method myMethod that returns an instance of ParentClass. You also have two classes, ParentClass and ChildClass, where ChildClass is a subclass of ParentClass. Finally, you have a class MyClass that implements MyInterface, providing an implementation of the myMethod method to return an instance of ChildClass. Here's a breakdown of what your code does:

MyInterface is an interface with a method myMethod that returns an instance of ParentClass.
ParentClass is a class with a method getClassName that returns the string "ParentClass."
ChildClass is a subclass of ParentClass. It overrides the getClassName method to return the string "ChildClass."
MyClass is a class that implements MyInterface. It provides an implementation of the myMethod method that returns an instance of ChildClass.
In the Main class's main method, you create an instance of MyClass named myInterface.
You call the myMethod method on the myInterface object, which returns an instance of ChildClass.
You assign the result to a ParentClass reference variable, result.
Finally, you call the getClassName method on the result object and print the result to the console.

Source Code

interface MyInterface
{
    ParentClass myMethod();
}
 
class ParentClass
{
    String getClassName()
	{
        return "ParentClass";
    }
}
 
class ChildClass extends ParentClass
{
    String getClassName()
	{
        return "ChildClass";
    }
}
 
class MyClass implements MyInterface
{
    @Override
    public ChildClass myMethod()
	{
        return new ChildClass();
    }
}
 
public class Main
{
    public static void main(String[] args)
	{
        MyInterface myInterface = new MyClass();
        ParentClass result = myInterface.myMethod();
        System.out.println(result.getClassName());
    }
}

Output

ChildClass