code: public FindResults find(String id, ExternalSource externalSource, String language) throws MovieDbException {
          TmdbParameters parameters = new TmdbParameters();
          parameters.add(Param.ID, id);
          parameters.add(Param.LANGUAGE, language);
          parameters.add(Param.EXTERNAL_SOURCE, externalSource.getPropertyString());
  
          URL url = new ApiUrl(apiKey, MethodBase.FIND).buildUrl(parameters);
          String webpage = httpTools.getRequest(url);
  
          try {
              return MAPPER.readValue(webpage, FindResults.class);
          } catch (IOException ex) {
              throw new MovieDbException(ApiExceptionType.MAPPING_FAILED, "Failed to get find results", url, ex);
          }
      }
docs: You con use this method to find movies, tv series or persons using external ids.
  
  Supported query ids are
  <ul>
  <li>Movies: imdb_id</li>
  <li>People: imdb_id, freebase_mid, freebase_id, tvrage_id</li>
  <li>TV Series: imdb_id, freebase_mid, freebase_id, tvdb_id, tvrage_id</li>
  <li>TV Seasons: freebase_mid, freebase_id, tvdb_id, tvrage_id</li>
  <li>TV Episodes: imdb_id, freebase_mid, freebase_id, tvdb_id, tvrage_idimdb_id, freebase_mid, freebase_id, tvrage_id,
  tvdb_id.
  </ul>
  
  For details see http://docs.themoviedb.apiary.io/#find
  
  @param id the external id
  @param externalSource one of {@link ExternalSource}.
  @param language the language
  @return
  @throws MovieDbException