250+ TOP MCQs on Inheritance – 1 and Answers [2024]

Java MCQs on Inheritance of Java Programming Language.

1. Which of this keyword must be used to inherit a class?
a) super
b) this
c) extent
d) extends

Answer: d
Clarification: None.

2. A class member declared protected becomes a member of subclass of which type?
a) public member
b) private member
c) protected member
d) static member

Answer: b
Clarification: A class member declared protected becomes a private member of subclass.

3. Which of these is correct way of inheriting class A by class B?
a) class B + class A {}
b) class B inherits class A {}
c) class B extends A {}
d) class B extends class A {}

Answer: c
Clarification: None.

4. Which two classes use the Shape class correctly?

A. public class Circle implements Shape 
   {
    private int radius;
   }
B. public abstract class Circle extends Shape 
   {
    private int radius;
   }
C. public class Circle extends Shape 
   {
   private int radius;
   public void draw();
   }
D. public abstract class Circle implements Shape 
   {
    private int radius;
    public void draw();
   }
E. public class Circle extends Shape 
   {
    private int radius;
    public void draw()
    {
     /* code here */
    }
   }
F. public abstract class Circle implements Shape 
   {
     private int radius;
     public void draw() 
     { 
      /* code here */ 
     }
   }

a) B,E
b) A,C
c) C,E
d) T,H

Answer: a
Clarification: If one is extending any class, then they should use extends keyword not implements.

5. What will be the output of the following Java program?

```
    class A 
```
```
    {
```
```
        int i;
```
```
        void display() 
```
```
        {
```
```
            System.out.println(i);
```
```
        }
```
```
    }    
```
```
    class B extends A 
```
```
    {
```
```
        int j;
```
```
        void display() 
```
```
        {
```
```
            System.out.println(j);
```
```
        }
```
```
    }    
```
```
    class inheritance_demo 
```
```
    {
```

        public static void main(String args[])

```
        {
```
```
            B obj = new B();
```
```
            obj.i=1;
```
```
            obj.j=2;   
```
```
            obj.display();     
```
```
        }
```
```
   }
```

a) 0
b) 1
c) 2
d) Compilation Error

Answer: c
Clarification: Class A & class B both contain display() method, class B inherits class A, when display() method is called by object of class B, display() method of class B is executed rather than that of Class A.
output:

$ javac inheritance_demo.java 
$ java inheritance_demo 
2

6. What will be the output of the following Java program?

```
    class A 
```
```
    {
```
```
        int i;
```
```
    }    
```
```
    class B extends A 
```
```
    {
```
```
        int j;
```
```
        void display() 
```
```
        {
```
```
            super.i = j + 1;
```

            System.out.println(j + " " + i);

```
        }
```
```
    }    
```
```
    class inheritance 
```
```
    {
```

        public static void main(String args[])

```
        {
```
```
            B obj = new B();
```
```
            obj.i=1;
```
```
            obj.j=2;   
```
```
            obj.display();     
```
```
        }
```
```
   }
```

a) 2 2
b) 3 3
c) 2 3
d) 3 2

Answer: c
Clarification: None
output:

$ javac inheritance.java
$ java inheritance
2 3

7. What will be the output of the following Java program?

```
    class A 
```
```
    {
```
```
        public int i;
```
```
        public int j;
```
```
        A() 
```
```
        {
```
```
            i = 1;
```
```
            j = 2;
```
```
	}
```
```
    }    
```
```
    class B extends A 
```
```
    {
```
```
        int a;
```
```
        B() 
```
```
        {
```
```
            super();
```
```
        } 
```
```
    }    
```
```
    class super_use 
```
```
    {
```

        public static void main(String args[])

```
        {
```
```
            B obj = new B();
```

            System.out.println(obj.i + " " + obj.j)

```
        }
```
```
   }
```

a) 1 2
b) 2 1
c) Runtime Error
d) Compilation Error

Answer: a
Clarification: Keyword super is used to call constructor of class A by constructor of class B. Constructor of a initializes i & j to 1 & 2 respectively.
output:

$ javac super_use.java
$ java super_use
1 2

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