Problem:
Swapping Two Numbers

Write a program which reads two integers x and y, and prints them in ascending order.

Input

The input consists of multiple datasets. Each dataset consists of two integers x and y separated by a single space.

The input ends with two 0 (when both x and y are zero). Your program should not process for these terminal symbols.

Output

For each dataset, print x and y in ascending order in a line. Put a single space between x and y.

Constraints

0 ≤ x, y ≤ 10000

the number of datasets ≤ 3000

Sample Input

3 2
2 2
5 3
0 0

Sample Output

2 3
2 2
3 5

Solution in JAVA (judge verdict: Wrong Answer)

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.NoSuchElementException;
import java.util.StringTokenizer;

class SwappingTwoNumbers extends ArrayList<Integer[]> {

	private static final int DATA_MAX = 10000;
	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;
	
	public SwappingTwoNumbers() {
		
	}
	
	private boolean check(int x, int y) {
		if (DATA_MAX < x || DATA_MAX < y) {
			return false;
		}
		return true;
	}
	private boolean read() {
		BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
		while (true) {
			try {
				Integer data[] = new Integer[]{0, 0};
				String s = br.readLine();
				StringTokenizer st = new StringTokenizer(s, " ");
				data[0] = Integer.parseInt(st.nextToken());
				data[1] = Integer.parseInt(st.nextToken());
				if (0 == data[0] && 0 == data[1]) {
					break;
				}
				if (!check(data[0], data[1])) {
					return false;
				}
				add(data);
			} catch (IOException e) {
				e.printStackTrace();
			} catch (NoSuchElementException e2) {
				e2.printStackTrace();
			}
			
		}
			
		return true;
	}
	
	private void swap() {
		for (int i = 0; i < size(); i++) {
			int tmp = get(i)[0];
			get(i)[0] = get(i)[1];
			get(i)[1] = tmp;
			
		}
	}
	
	public void run() {
		if (!read()) {
			System.out.println("入力エラー");
		}
		swap();
		
		for (int i = 0; i < size(); i++) {
			System.out.println(get(i)[0] + " " + get(i)[1]);
		}
	}
}
public class Main {

	public static void main(String[] args) {

		new SwappingTwoNumbers().run();
	}

}