Shallow copy in java example program

• We create exact copy of the object using Cloneable in java.
• We need to override object class clone() method.
• This is also called clone of the object.
• So we can create copy of object using two different way
  
  1. Shallow copy
  2. Depp copy

Shallow copy / Shallow cloning in java

• In Shallow copy object reference will be copied instead of copying whole data of the object.
• So the newly created object will be another reference for existing with same data means shallow copy of the object.
• Whenever we change data in the original object same changes made to new object also because both are pointing to same object.

Program #1: Java example program to demonstrate shallow copy / shallow cloning



Example:

1. package com.shallowcopyvsdeppcopy;
2. 
   
3. public class Example{
4. int a;
5. int b;
6. 
   
7. Example(int a, int b){
8.     this.a=a;
9.     this.b=b;
10. }
11. 
    
12. }

Empclone :

1. package com.shallowcopyvsdeppcopy;
2. 
   
3. public class Empclone implements Cloneable {
4. 
   
5.     Example e;
6.     int a;
7.    
8.     Empclone (int a, Example es){
9.         this.a=a;
10.         this.e=e;
11.       
12.     }
13.    
14.  public Object clone()throws CloneNotSupportedException{
15.       
16.         return super.clone();
17.  }
18.           
19.    
20. public static void main(String[] args) {
21.     
22.         Empclone a= new Empclone (2, new Example(3,3));
23.         Empclone b=null;
24.    
25.         try {
26.              b=(Empclone )a.clone();
27.           
28.         } catch (CloneNotSupportedException e) {
29.             
30.             e.printStackTrace();
31.         }
32.         System.out.println(a.e.a);
33.         System.out.println(b.e.a);
34.       
35.         a.e.a=12;
36.         System.out.println(a.e.a);
37.         System.out.println(b.e.a);
38.     }
39. 
    
40. }

Output:

1. 3
2. 3
3. 12
4. 12