code: public static boolean isEmpty(final Collection<String> c) {
          if (c == null || c.isEmpty()) {
              return false;
          }
          for (final String text : c) {
              if (isNotEmpty(text)) {
                  return false;
              }
          }
          return true;
      }
docs: Check if a collection of a string is empty.
  
  @param c
  @return