Java Bootcamp Day 4

What is the primary purpose of inheritance in Java?

• Code repetition

• Code hiding

• Code reuse

• Code encryption

Which keyword is used to inherit a class in Java?

• implements

• inherits

• extend

• extends

Which of the following inheritance types is not supported directly in Java?

• Single

• Multilevel

• Hierarchical

• Multiple (via classes)

Consider the following code:

class Animal {

void makeSound() { System.out.println("Animal sound"); }

}

class Dog extends Animal {

void makeSound() { System.out.println("Bark"); }

}

What will new Dog().makeSound(); output?

• Animal sound

• Bark

• Error

• Null

What is achieved by using the super keyword in Java?

• Access static members

• Access parent class members

• Access child class members

• Access private members of parent class

What will be the output?

class A {

A() { System.out.print("A "); }

}

class B extends A {

B() { System.out.print("B "); }

}

public class Test {

public static void main(String[] args) {

new B();

}

}

• A B

• B A

• AB

• Compilation Error

What concept does method overriding support in Java?

• Encapsulation

• Inheritance

• Abstraction

• Polymorphism

Which is true about constructors and inheritance?

• Child class inherits parent constructor

• Child class cannot access parent constructor

• Constructor is not inherited but invoked via super()

• Constructors are inherited like methods

Which concept binds data and code together while hiding the implementation?

• Inheritance

• Abstraction

• Encapsulation

• Polymorphism

How is encapsulation implemented in Java?

• By using abstract classes

• By making data members private and providing public getters/setters

• By making all members public

• By using final methods