public static String removeDuplicates(String string) {
		if (string == null) {
			return null;
		}
		/* empty string */
		if (string.length() == 0) {
			return "";
		}

		if (string.length() == 1) {
			return string;
		}
		if (string.charAt(0) == string.charAt(1)) {
			return removeDuplicates(string.substring(1));
		} else {
			return string.charAt(0) + removeDuplicates(string.substring(1));
		}
	}