Inheritance and Polymorphism – Multiple Choice Questions (MCQs)

1. 1. What is inheritance in Java?

   • A. The ability of an object to take on many forms
   • B. The mechanism of deriving a new class from an existing one
   • C. The process of hiding the implementation details of an object
   • D. The way objects interact with each other

2. 2. Which keyword is used to implement inheritance in Java?

   • A. inherits
   • B. extends
   • C. implements
   • D. subclass

3. 3. What is a superclass (or parent class) in Java?

   • A. The class that is created first
   • B. The class from which another class inherits
   • C. A class with no methods
   • D. The main class in a program

4. 4. What is a subclass (or child class) in Java?

   • A. The class that inherits from another class
   • B. A class that cannot have instances
   • C. A class with only static methods
   • D. The class that is created last

5. 5. Can a class inherit from multiple classes directly in Java?

   • A. Yes
   • B. No
   • C. Only interfaces
   • D. Only abstract classes

6. 6. What is the output of the following code? `class Animal { void makeSound() { System.out.println(\Generic sound\"); } } class Dog extends Animal { void makeSound() { System.out.println(\""Woof\""); } public static void main(String[] args) { Dog myDog = new Dog(); myDog.makeSound(); } }`"""

   • A. Generic sound
   • B. Woof
   • C. Error
   • D. None

7. 7. What is method overriding in Java?

   • A. Defining a new method in a subclass with the same name and signature as a method in its superclass
   • B. Calling a method from the superclass
   • C. Combining methods from different classes
   • D. Deleting a method from a superclass

8. 8. How do you call a method of the superclass from within a subclass method that has overridden it?

   • A. Using `this.superclassMethod()`
   • B. Using `super.superclassMethod()`
   • C. Using `ParentClass.superclassMethod(this)`
   • D. Using `self.superclassMethod()`

9. 9. What is the output of the following code? `class Parent { void greet() { System.out.println(\Hello from Parent\"); } } class Child extends Parent { void greet() { super.greet(); System.out.println(\""Hello from Child\""); } public static void main(String[] args) { Child myChild = new Child(); myChild.greet(); } }`"""

   • A. Hello from Child
   • B. Hello from Parent\nHello from Child
   • C. Hello from Parent
   • D. Error

10. 10. What is polymorphism in Java?

    • A. The ability of an object to take on many forms
    • B. The mechanism of deriving a new class from an existing one
    • C. The bundling of data and methods
    • D. The way objects interact with each other

11. 11. Which of the following is NOT a way to achieve polymorphism in Java?

    • A. Method overloading
    • B. Method overriding
    • C. Using interfaces
    • D. Class inheritance

12. 12. What is compile-time polymorphism (static binding) in Java?

    • A. Polymorphism achieved through method overriding
    • B. Polymorphism achieved through method overloading
    • C. Polymorphism achieved through inheritance
    • D. Polymorphism achieved through interfaces