Clone() Method Quiz

Clone() Method Quiz | Cloning of objects means creating an exact duplicate copy with the current object state. In Java, to perform cloning clone() method is given in java.lang.Object class. Also see:- Object Class Quiz Set-1, Java Hashcode Value Quiz, Java Equals() Method Quiz

Q1) What is the return type of clone() method in the Object class?

a) Class
b) Object
c) int
d) String

Q2) clone() method of Object class is?

a) public method
b) protected method
c) private method
d) None of these

Q3) Which of the following statement is not applicable for the clone() method of Object class?

a) To execute the clone() method on an object the class must implement java.lang.Cloneable interface.
b) It is a protected method.
c) It throws CloneNotSupportException.
d) It is a static method.

Q4) Which of the following statement is true about the Cloneable interface?

a) It doesn’t contain any method.
b) It contains only one method.
c) It contains multiple methods.
d) None of these

Q5) Find the output of the below Java program?

class Student implements Cloneable {
  int id;
  Student(int id) {
    this.id = id;
  }

  public static void main(String[] args) 
        throws CloneNotSupportedException {
    Student s1 = new Student(9);
    Student s2 = s1;

    s1.id = 18;
    System.out.println(s1.id+" "+s2.id);
  }
}

a) 9 9
b) 18 9
c) 9 18
d) 18 18

Q6) Find the output of the below Java program?

class Student implements Cloneable {
  int id;
  Student(int id) {
    this.id = id;
  }

  public static void main(String[] args) 
        throws CloneNotSupportedException {
    Student s1 = new Student(9);
    Student s2 = (Student) s1.clone();

    s1.id = 18;
    System.out.println(s1.id+" "+s2.id);
  }
}

a) 9 9
b) 18 9
c) 9 18
d) 18 18

Q7) Find the output of the below Java program?

class P {
  int x = 10;
}

class Q extends P {
  int y = 20;
}

class R extends Q implements Cloneable {
  int z = 30;

  public static void main(String[] args) 
              throws CloneNotSupportedException{
     R r1 = new R();
     R r2 = (R) r1.clone();
     r1.x = 100;
     r1.y = 200;
     r1.z = 300;
     System.out.println(r2.x+" "+r2.y+" "+r2.z);
  }
}

a) 100 200 300
b) 10 20 30
c) 10 20 300
d) 100 200 30

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