Inheritance in Java MCQ - Quiz

Q: A class member declared protected becomes member of subclass of which type?

Q: What is the output of this program?

      class A 
    {
        public int i;
        private int j;
    }    
    class B extends A 
    {
        void display() 
        {
            super.j = super.i + 1;
            System.out.println(super.i + " " + super.j);
        }
    }    
    class inheritance 
    {
        public static void main(String args[])
        {
            B obj = new B();
            obj.i=1;
            obj.j=2;   
            obj.display();     
        }
   }

Q: What is the output of this 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)     
        }
   }

Q: What is the output of this program?

class A 
    {
        public int i;
        protected int j;
    }    
    class B extends A 
    {
        int j;
        void display() 
        {
            super.j = 3;
            System.out.println(i + " " + j);
        }
    }    
    class Output 
    {
        public static void main(String args[])
        {
            B obj = new B();
            obj.i=1;
            obj.j=2;   
            obj.display();     
        }
   }

Q: Which of the following is true?

1. A class can extend more than one class.
2. A class can extend only one class but many interfaces.
3. An interface can extend many interfaces.
4. An interface can implement many interfaces.
5. A class can extend one class and implement many interfaces.

Q: What will be the output?

interface A{
	public void method1();
}
class One implements A{
	public void method1(){
		System.out.println("Class One method1");
	}
}
class Two extends One{
	public void method1(){
		System.out.println("Class Two method1");
	}
}
public class Test extends Two{
	public static void main(String[] args){
		A a = new Two();
		a.method1();
	}
}

Q: What will be printed after executing following program code?

class Base{
	int value = 0;
        Base(){
        	addValue();
        }
        void addValue(){
        	value += 10;
        }
        int getValue(){
        	return value;
        }
}
class Derived extends Base{
	Derived(){
		addValue();
	}
	void addValue(){
		value +=  20;
	}
}
public class Test{
	public static void main(String[] args){
		Base b = new Derived();
		System.out.println(b.getValue());
	}
}

Q: What will be the output?

class A{
      int i = 10;
      public void printValue(){
            System.out.print("Value-A");
      }
}

class B extends A{
      int i = 12;
      public void printValue(){
            System.out.print("Value-B");
      }
}

public class Test{
      public static void main(String args[]){
            A a = new B();
            a.printValue();
            System.out.print(a.i);
      }
}

Q: What will be the result of compiling and running the given code?

class A{
      int b=10;
      private A(){
            this.b=7;
      }
      int f(){
            return b;
      }
}
class B extends A{
      int b;
}
public class Test{
      public static void main(String[] args){
            A a = new B();
            System.out.println(a.f());
      }
}

Q: A mechanism where one class acquires the properties of another class: