Alpha Preparation- Strange Order

Забих тотално.
Как да се оттърва от паразитната запетя накрая:
import java.util.Scanner;

public class StrangeOrder {
public static void main(String[] args) {
Scanner scanner = new Scanner(System.in);

    String[] input = scanner.nextLine().split(",");

    int[] arr = new int[input.length];

    for (int i = 0; i < input.length; i++) {
        arr[i] = Integer.parseInt(input[i]);
    }

    int[] negativeArr = new int[arr.length];
    int[] positiveArr = new int[arr.length];
    int[] zeroArr = new int[arr.length];
    String negative = "";
    String positive = "";
    String zero = "";

    for (int i = 0; i < arr.length; i++) {
        if (arr[i] < 0) {
            negativeArr[i] = arr[i];
            negative = negative + negativeArr[i] + ",";
        } else if (arr[i] > 0) {
            positiveArr[i] = arr[i];
            positive = positive + positiveArr[i] + ",";

        } else if (arr[i] == 0) {
            zeroArr[i] = arr[i];
            zero = zero + zeroArr[i] + ",";
        }
    }
    System.out.println(negative + zero + positive);
}

}

Здравей,
най-бързо така:

System.out.println(negative + zero + positive.substring(0, positive.length()-1));