code: public static boolean isEqualCollection(Collection<String> list1, Collection<String> list2) {
          Validate.notNull(list1);
          Validate.notNull(list2);
  
          boolean result = true;
  
          if (list1.size() == list2.size()) {
              for (final String currentString : list1) {
                  if (!list2.contains(currentString)) {
                      result = false;
                      break;
                  }
              }
          } else {
              result = false;
          }
  
          return result;
      }
docs: Determines whether the provided collections of strings are equal. Equality is considered:
  
  <ul>
  <li>Both lists are empty, or</li>
  <li>Both lists are of the same size and contain the same elements.</li>
  </ul>
  
  
  @param list1
  the first list, may not be {@code null}
  @param list2
  the second list, may not be {@code null}
  @return true if the lists are equal, false otherwise