Split X into N uniformly-distributed pieces (java)

Split.java

import java.util.ArrayList;
import java.util.Random;
import java.lang.Math;

public class Split {
	private static Random rand = new Random();

	public static void main(String[] args) {
		ArrayList<Integer> list = splitNum(Integer.valueOf(args[0]), Integer.valueOf(args[1]));

		System.out.println("sum: " + sumList(list));
		printList(list);
	}

	private static ArrayList<Integer> splitNum(int n, int numPieces) {
		ArrayList<Integer> rtn = new ArrayList<Integer>();
		int mid = n / numPieces;
		int delta = 0;

		for (int i = 0; i < numPieces; i++) {
			if (i % 2 == 0) {
				delta = randInt(0, mid);
			} else {
				delta = -delta;
			}

			if (numPieces % 2 != 0 && i == numPieces - 1) {
				delta = 0;
			}

			rtn.add(mid + delta);
		}	

		int sum = sumList(rtn);

		int diff;

		if (sum > n) {
			diff = n - sum;
		} else {
			diff = sum - n;
		}

		if (diff != 0) {
			for (int i = 0; i < Math.abs(diff); i++) {
				int index = randInt(0, numPieces - 1);

				if (diff > 0) {
					rtn.set(index, rtn.get(index) - 1);
				} else {
					rtn.set(index, rtn.get(index) + 1);
				}
			}
		}

		return rtn;
	}

	private static int randInt(int min, int max) {
		return rand.nextInt((max - min) + 1) + min;
	}

	private static int sumList(ArrayList<Integer> list) {
		int rtn = 0;
		for (int n : list) {
			rtn += n;
		}

		return rtn;
	}

	private static void printList(ArrayList<Integer> list) {
		System.out.print("[");

		for (int i = 0; i < list.size(); i++)
		{
			System.out.print(list.get(i));
			if (i != list.size() - 1) {
				System.out.print(", ");
			}
		}
		System.out.println("]");
	}
}