Java Questions & Answers – Method overriding

Created on June 10, 2020 By

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Java Questions & Answers – Method overriding

1 / 10

1. Which of this keyword can be used in a subclass to call the constructor of superclass?

A. super

B. this

C. extent

D. extends

2 / 10

2. What is the process of defining a method in a subclass having same name & type signature as a method in its superclass?

A. Method overloading

B. Method overriding

C. Method hiding

D. None of the mentioned

3 / 10

3. Which of these keywords can be used to prevent Method overriding?

A. static

B. constant

C. protected

D. final

4 / 10

4. Which of these is correct way of calling a constructor having no parameters, of superclass A by subclass B?

A. super(void);

B. superclass.();

C. super.A();

D. super();

5 / 10

5. At line number 2 in the following code, choose 3 valid data-type attributes/qualifiers among “final, static, native, public, private, abstract, protected”

```
public interface Status
```
```
   {
```

        /* insert qualifier here */ int MY_VALUE = 10;

```
   }
```

A. final, native, private

B. final, static, protected

C. final, private, abstract

D. final, static, public

6 / 10

6. Which of these is supported by method overriding in Java?

A. Abstraction

B. Encapsulation

C. Polymorphism

D. None of the mentioned

7 / 10

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

```
 class Alligator
```
```
 {
```

  public static void main(String[] args)

```
   {
```

   int []x[] = {{1,2}, {3,4,5}, {6,7,8,9}};

```
   int [][]y = x;
```
```
   System.out.println(y[2][1]);
```
```
}
```
```
 
```

A. 2

B. 3

C. 7

D. Compilation Error

8 / 10

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

```
   final class A
```
```
    {
```
```
         int i;
```
```
    }
```
```
    class B extends A
```
```
    {
```
```
        int j;
```

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

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

        public static void main(String args[])

```
        {
```
```
            B obj = new B();
```
```
            obj.display();
```
```
        }
```
```
   }
```

A. 2 2

B. 3 3

C. Runtime Error

D. Compilation Error

9 / 10

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

```
  class Abc
```
```
  {
```

      public static void main(String[]args)

```
      {
```

          String[] elements = { "for", "tea", "too" };

          String first = (elements.length > 0) ? elements[0]: null;

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

A. Compilation error

B. An exception is thrown at run time

C. The variable first is set to null

D. The variable first is set to elements[0]

10 / 10

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

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

        public static void main(String args[])

```
        {
```
```
            B obj2 = new B();
```
```
            obj2.i = 1;
```
```
            obj2.j = 2;
```
```
            A r;
```
```
            r = obj2;
```
```
            r.display();
```
```
        }
```
```
   }
```

A. 1

B. 2

C. 3

D. 4

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