java remove duplicates from string

/**
 * @author lautturi.com 
 * Java example: remove duplicate elements from java String
 */

import java.util.*;

public class Lautturi {
	public static void main(String[] args) {

		String str1 = "ABCDAABBCCE";
		String output = "";

		for (int a = 0; a <= str1.length() - 1; a++) {
			if (output.contains("" + str1.charAt(a))) {
				continue;
			}
			output += str1.charAt(a);
		}
		System.out.println(output);
	}
}

output:

ABCDE