What is object cloning in Java

Question

May I know how to create an exact copy of object in Java?

Answer 1

Object cloning means to create an exact copy of the original object.

If a class needs to support cloning, it must implement java.lang.Cloneable interface and override clone() method from Object class. Syntax of the clone() method is :

protected Object clone() throws CloneNotSupportedException

If the object’s class doesn’t implement Cloneable interface then it throws an exception ‘CloneNotSupportedException’ .

Example:

class Test implements Cloneable

{

    int a;

    int b;

  

    // Parameterized constructor

    Test(int a, int b)

    {

        this.a = a;

        this.b = b;

    }

  

    // Method that calls clone()

    Test cloning()

    {

        try

        {

            return (Test) super.clone();

        }

        catch(CloneNotSupportedException e)

        {

            System.out.println("CloneNotSupportedException is caught");

            return this;

        }

    }

}

  

class demo

{

    public static void main(String args[])

    {

        Test obj1 = new Test(1, 2);

        Test obj2 = obj1.cloning();

        obj1.a = 3;

        obj1.b = 4;

        System.out.println("Object2 is a clone of object1");

        System.out.println("obj1.a = " + obj1.a + " obj1.b = " + obj1.b);

        System.out.println("obj2.a = " + obj2.a + " obj2.b = " + obj2.b);

    }

}