code: public static boolean hasMimeType(String mimeType) {
          if (mimeType == null || mimeType.length() == 0) {
              return false;
          }
          return mimeTypeToExtensionMap.containsKey(mimeType);
      }
docs: Returns true if the given MIME type has an entry in the map.
  
  @param mimeType A MIME type (i.e. text/plain)
  @return True iff there is a mimeType entry in the map.