Java Autoboxing MCQs Questions | Java Program MCQs Page-8 section-1

71.
What does Liskov substitution principle specify?

A. parent class can be substituted by child class

B. child class can be substituted by parent class

C. parent class cannot be substituted by child class

D. No classes can be replaced by each other

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72.

What will be the correct option of the following Java code snippet?

interface ICust 
{
}
class RegularCustomer implements ICust 
{
}
class OneTimeCustomer implements ICust 
{
}

A. ICust can be replaced with RegularCustomer

B. RegularCustomer can be replaced with OneTimeCustomer

C. OneTimeCustomer can be replaced with RegularCustomer

D. We can instantiate objects of ICust

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73.

What will be the output of the following Java code snippet?

public class Shape 
{
	public int area()
        {
		return 1;
	}
}
public class Square extends Shape 
{
	public int area()
        {
		return 2;
	}
}
class Main() 
{
   public static void main(String[] args)
   {
	Shape shape = new Shape();
	Square square = new Square();
	shape = square;
	System.out.println(shape.area());
    }
}

A. Compilation failure

B. Runtime failure

C. 1

D. 2

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74.

What will be the output of the following Java code snippet?

public class Shape 
{
	public int area()
        {
		return 1;
	}
}
public class Rectangle extends Shape 
{
	public int area()
        {
		return 3;
	}
}
class Main() 
{
   public static void main(String[] args)
   {
	Shape shape = new Shape();
	Rectangle rect = new Rectangle();
	shape = rect;
	System.out.println(shape.area());
   }
}

A. Compilation failure

B. 3

C. 1

D. 2

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75.

What will be the output of the following Java code?

public class Shape 
{
	public int area()
        {
		return 1;
	}
}
public class Square extends Shape 
{
	public int area()
        {
		return 2;
	}
}
class Main() 
{
   public static void main(String[] args)
   {
	Shape shape = new Shape();
	Square square = new Square();
	square = shape;
	System.out.println(square.area());
   }
}

A. Compilation failure

B. 3

C. 1

D. 2

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76.

What will be the output of the following Java code?

public class Shape 
{
	public int area()
        {
		return 1;
	}
}
public class Square extends Shape 
{
	public int area()
        {
		return 2;
	}
}
public class Rectangle extends Shape 
{
	public int area()
        {
		return 3;
	}
}
class Main() 
{
   public static void main(String[] args)
   {
	Shape shape = new Shape();
	Square square = new Square();
    	Rectangle rect = new Rectangle();
	rect = (Rectangle)shape;
	System.out.println(square.area());
   }
}

A. Compilation failure

B. 3

C. Runtime Exception

D. 2

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77.

What will be the output of the following Java code?

public class Shape 
{
	public int area()
        {
		return 1;
	}
}
public class Square extends Shape 
{
	public int area()
        {
		return 2;
	}
}
public class Rectangle extends Shape 
{
	public int area()
        {
		return 3;
	}
}
class Main() 
{
      public static void main(String[] args)
      {
	 Shape shape = new Shape();
	 Square square = new Square();
   	 Rectangle rect = new Rectangle();
	 rect = (Rectangle)square;
	 System.out.println(square.area());
      }
}

A. Compilation failure

B. 3

C. Runtime Exception

D. 2

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78.

What will be the output of the following Java code?

public class Shape 
{
	public int area()
        {
		return 1;
	}
}
public class Square extends Shape 
{
	public int area()
        {
		return 2;
	}
}
public class Rectangle extends Shape 
{
	public int area()
        {
		return 3;
	}
}
class Main() 
{
       public static void main(String[] args)
       {
	 Shape shape = new Shape();
	 Square square = new Square();
   	 Rectangle rect = new Rectangle();
	 rect = (Rectangle)square;
	 System.out.println(square.area());
	}
}

A. Compilation failure

B. 3

C. Runtime Exception

D. 2

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79.

What will be the output of the following Java code?

public class Shape 
{
	public int area()
        {
		return 1;
	}
}
public class Square extends Shape 
{
	public int area()
        {
		return 2;
	}
}
public class Rectangle extends Shape 
{
	public int area()
        {
		return 3;
	}
}
public static void main(String[] args)
{
	 Shape shape = new Square();
   	 shape = new Rectangle();
	 System.out.println(shape.area());
}

A. Compilation failure

B. 3

C. Runtime Exception

D. 2

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80.

What will be the output of the following Java code?

public class Shape 
{
	public int area()
        {
		return 1;
	}
}
public class Square extends Shape 
{
	public int area()
        {
		return 2;
	}
}
public class Rectangle extends Shape 
{
	public int area()
        {
		return 3;
	}
}
public static void main(String[] args)
{
	 Shape square = new Square();
   	 Shape rect = new Rectangle();
     	 square = rect;
	 System.out.println(square.area());
}

A. Compilation failure

B. 3

C. Runtime Exception

D. 2

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Java Autoboxing MCQs Questions | Java Program MCQs

71. What does Liskov substitution principle specify?

Answer & Solution

72. What will be the correct option of the following Java code snippet? interface ICust { } class RegularCustomer implements ICust { } class OneTimeCustomer implements ICust { }

Answer & Solution

Answer & Solution

Answer & Solution

Answer & Solution

Answer & Solution

Answer & Solution

Answer & Solution

Answer & Solution

Answer & Solution

71.
What does Liskov substitution principle specify?

72.
What will be the correct option of the following Java code snippet?

`interface ICust { } class RegularCustomer implements ICust { } class OneTimeCustomer implements ICust { }`