הוספת מספר למערך קיים

package class1;

import java.util.Scanner;

public class tester {

    public static void main(String[] args) {
        int[] arrInt = {6,7,4,2};
        System.out.println("size of:"+arrInt.length);
        arrInt = addNum(arrInt,8);
        System.out.println("size of:"+arrInt.length); //5
    }

    public static int[] addNum(int[] oldArr,int newNum)
    {
        int[] returnArr = new int[oldArr.length+1];
        for (int counter=0;counter<oldArr.length;counter+=1)
        {
            returnArr[counter]=oldArr[counter];
        }
        returnArr[returnArr.length-1]=newNum;
        return returnArr;
    }
}