Please Explain this Java Array Reference Parameter Passing Behavior

Question

public class TestArray {
    public static void main(String[] args) {
        int[] ar = {1,2,3,4,5,6,7,8,9};

        shiftRight(ar);
        for (int i = 0; i <         


        

Answer 1

In Java, it's a misnomer to say that objects are passed by reference. It's more accurate to say that the reference to the object is passed by value.

You pass the array reference to reverseArray by value. The local parameter is a copy of the reference to the array. Later when you say

ar = temp;

You have only pointed the local ar to temp, not the original array reference ar from main.

On the other hand, in the shiftRight method, you have directly accessed the array through the copied reference, so the original array's contents change and the method works as expected.