Java Interview Guide : 200+ Interview Questions and Answers - Polymorphism and instanceof

This video tutorial covers advanced object-oriented programming concepts, focusing on polymorphism and the 'instance of' operator in Java. It explains polymorphism with examples, showing how the same code can exhibit different behaviors based on the object it references. The tutorial also delves into the 'instance of' operator, demonstrating its use in checking object types within class hierarchies and interfaces. Throughout the video, viewers are encouraged to engage with code examples to deepen their understanding.

Which of the following is NOT considered an advanced object-oriented concept discussed in the video?

• Inheritance

• Polymorphism

• Encapsulation

• Anonymous Classes

What is the primary characteristic of polymorphism?

• Same code, same behavior

• Different code, same behavior

• Same code, different behavior

• Different code, different behavior

In the context of polymorphism, what determines the method that gets called?

• The reference variable type

• The object type

• The class name

• The method name

Why can't you call a method defined in a subclass using a superclass reference variable?

• Because the method is private

• Because the reference variable type restricts accessible methods

• Because the method is static

• Because the method is abstract

What does the 'instance of' operator check in Java?

• If an object is a primitive type

• If an object is a specific class or interface type

• If an object is null

• If an object is a superclass

Can the 'instance of' operator be used with interfaces?

• Yes, but only with abstract classes

• No, it can only be used with classes

• No, it is not applicable to interfaces

• Yes, it can be used with both classes and interfaces

What will 'instance of' return if an object is checked against its superclass?

• False

• True

• Compilation error

• Null