code: public static String[] union(String[] arr1, String[] arr2) {
  		Set<String> set = new HashSet<String>();
  		for (String str : arr1) {
  			set.add(str);
  		}
  		for (String str : arr2) {
  			set.add(str);
  		}
  		String[] result = {};
  		return set.toArray(result);
  	}
docs: Arr1 union Arr2
  @param arr1
  @param arr2