Inheritance in Java MCQ - Quiz

Determine output: 
class A{
	public void method1(){
		System.out.print("Class A method1");
	}
}
class B extends A{
	public void method2(){
		System.out.print("Class B method2");
	}
}
class C extends B{
	public void method2(){
		System.out.print("Class C method2");
	}	
	public void method3(){
		System.out.print("Class C method3");
	}
}
public class Test{
	public static void main(String args[]){
		A a = new A();
		C c = new C();		
		c.method2();
		a = c;
		a.method3();
	}
}

  • A Class B method2 Class C method3
  • B Class C method2 Class C method3
  • C Compilation Error
  • D Runtime exception

What will be the result after compiling this code? 
class SuperClass{
      public int doIt(String str, Integer... data)throws Exception{
            String signature = "(String, Integer[])";
            System.out.println(str + " " + signature);
            return 1;
      }
}

public class Test extends SuperClass{
      public int doIt(String str, Integer... data){
            String signature = "(String, Integer[])";
            System.out.println("Overridden: " + str + " " +signature);
            return 0;
      }

      public static void main(String... args){
            SuperClass sb = new Test();
            sb.doIt("hello", 3);
      }
}

  • A Overridden: hello (String, Integer[])
  • B hello (String, Integer[])
  • C Compilation fails
  • D None of these

Which is true?
  • A "X extends Y" is correct if and only if X is a class and Y is an interface
  • B "X extends Y" is correct if and only if X is an interface and Y is a class
  • C "X extends Y" is correct if X and Y are either both classes or both interfaces
  • D "X extends Y" is correct for all combinations of X and Y being classes and/or interfaces

Which of these keywords is used to refer to member of base class from a sub class?
  • A upper
  • B super
  • C this
  • D none of the mentioned

What is the result of compiling and running the following code? 
class Base{
        public Base(){
                System.out.print("Base");
        }
}
public class Derived extends Base{
        public Derived(){
                this("Examveda");
                System.out.print("Derived");
        }
        public Derived(String s){
                System.out.print(s);
        }
        public static void main(String[] args){
                new Derived();
        }
}

  • A ExamvedaDerived
  • B ExamvedaBaseDerived
  • C BaseExamvedaDerived
  • D ExamvedaDerivedBase

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();
	}
}

  • A Compilation Error
  • B Class One method1
  • C Class One method1
  • D Throws a NoSuchMethodException at runtime.

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 {}

What will be the output? 
class One{
      final int a = 15;
}

class Two extends One{
      final int a = 20;
}

public class Test extends Two{
      final int a = 30;

      public static void main(String args[]){
            Test t = new One();
            System.out.print(t.a);
      }
}

  • A 15
  • B 20
  • C 30
  • D Compiler Error

What will be the output? 
class Parent{
      public void method(){
            System.out.println("Hi i am parent");
      }
}
public class Child extends Parent{
      protected void method(){
            System.out.println("Hi i am Child");
      }
      public static void main(String args[]){
            Child child = new Child();
            child.method();
      }
}

  • A Compiles successfully and print
  • B Compiles successfully and print
  • C Compile time error
  • D Run Time error