Why does one arraylist change when a copy of it is modified

Question

Its probably a very simple one but its\' still confusing me!

import java.util.ArrayList;

public class Sample {
    ArrayList i = new ArrayLis         


        

Answer 1

Let me do this in the following way for you:

ArrayList i = new ArrayList<>();
ArrayList j = new ArrayList<>();

// checking hash code before j = i;
System.out.println(System.identityHashCode(i));
System.out.println(System.identityHashCode(j));

j = i;

// checking hash code after j = i;
System.out.println(System.identityHashCode(i));
System.out.println(System.identityHashCode(j));

compare both the values if they are same that means after j=i; ArrayList j is now pointing to ArrayList i

In my machine o/p was:

30269696 //hashCode of i
24052850 //hashCode of j before j = i;

30269696 //hashCode of i and j are same after j = i that means they are pointing to same reference and hence change in one reflects on the other.
30269696