code: public static String[] minus(String[] arr1, String[] arr2) {
  		LinkedList<String> list = new LinkedList<String>();
  		LinkedList<String> history = new LinkedList<String>();
  		String[] longerArr = arr1;
  		String[] shorterArr = arr2;
  		if (arr1.length > arr2.length) {
  			longerArr = arr2;
  			shorterArr = arr1;
  		}
  		for (String str : longerArr) {
  			if (!list.contains(str)) {
  				list.add(str);
  			}
  		}
  		for (String str : shorterArr) {
  			if (list.contains(str)) {
  				history.add(str);
  				list.remove(str);
  			} else {
  				if (!history.contains(str)) {
  					list.add(str);
  				}
  			}
  		}
  
  		String[] result = {};
  		return list.toArray(result);
  	}
docs: Arr1 minus Arr2
  @param arr1
  @param arr2