Array assignment and reference in Java

Question

public class Test {
    public static void main(String[] args) {
        int[] a = {1, 2, 3, 4, 5};
        int[] b = a;
        int[] c = {6, 7, 8};
        a = c;
         


        

Answer 1

Suppose you think of an object as a house, and a reference as a piece of paper with the address of a house written on it. a, b, and c are all references. So when you say

    int[] a = {1, 2, 3, 4, 5};

you're building a house with 1, 2, 3, 4, and 5 in it; and a is a piece of paper with the address of that house.

    int[] b = a;

b is another reference, which means it's another piece of paper. But it has the address of the same house on it.

    int[] c = {6, 7, 8};
    a = c;

Now we build a new house and put 6, 7, and 8 into it. c will be a piece of paper with the address of the new house. When we say a = c, then the slip of paper that used to be a is thrown out, and we make a new piece of paper with the address of the new house. That's the new value of a.

But b was a separate piece of paper. It hasn't changed. Nothing we've done has changed it.

References are like that.