code: public CollectionInfo getCollectionInfo(int collectionId, String language) throws MovieDbException {
          TmdbParameters parameters = new TmdbParameters();
          parameters.add(Param.ID, collectionId);
          parameters.add(Param.LANGUAGE, language);
  
          URL url = new ApiUrl(apiKey, MethodBase.COLLECTION).buildUrl(parameters);
          String webpage = httpTools.getRequest(url);
  
          try {
              return MAPPER.readValue(webpage, CollectionInfo.class);
          } catch (IOException ex) {
              throw new MovieDbException(ApiExceptionType.MAPPING_FAILED, "Failed to get collection information", url, ex);
          }
      }
docs: This method is used to retrieve all of the basic information about a
  movie collection.
  
  You can get the ID needed for this method by making a getMovieInfo
  request for the belongs_to_collection.
  
  @param collectionId
  @param language
  @return
  @throws MovieDbException