integer sums equal .... in linear time

LinearSums.java

import java.util.Random;

public class LinearSums {

    public static void print(int i) {System.out.println(i);}
    public static void print(String s) {System.out.println(s);}

    public static void main(String[] args) {
        Random rn = new Random();

        final int ARR_SIZE = 30;
        final int NUM_MAX  = 20;
        final int DESIRED_NUM = 10;

        // Randomly generates an array with possible numbers 0 to NUM_MAX with the size of ARR_SIZE
        int[] arr = new int[ARR_SIZE];
        for (int i = 0 ; i < ARR_SIZE ; i++) {
            arr[i] = rn.nextInt(NUM_MAX);
        }

        //If DESIRED_NUM is less than ARR_SIZE code won't work.
        if (DESIRED_NUM < ARR_SIZE) {

            for (int i = 0; i < ARR_SIZE; i++) {
                // For every number less than DESIRED_NUM, we add that number NUM_MAX.
                // So if arr[i] / NUM_MAX > 0 this means number i exists.
                // When we access the arr[i] we mod it in NUM_MAX because the value will be allways less than NUM_MAX
                if (DESIRED_NUM - arr[i] % NUM_MAX >= 0)
                    arr[arr[i] % NUM_MAX] += NUM_MAX;

            }

            for (int i = 0; i <= DESIRED_NUM; i++) {
                // Checks if we have number i and desired_num - i
                if (arr[i] / NUM_MAX > 0 && arr[DESIRED_NUM - i] / NUM_MAX > 0)
                    System.out.println(i + ", " + (DESIRED_NUM - i));


            }
        }
    }
}