code: @Override
      public synchronized void close() {
          if (isOpen()) {
              clearCache();
              closeStatements();
              try {
                  connection.close();
              } catch (SQLException ex) {
                  LOGGER.error("There was an error attempting to close the CveDB, see the log for more details.");
                  LOGGER.debug("", ex);
              } catch (Throwable ex) {
                  LOGGER.error("There was an exception attempting to close the CveDB, see the log for more details.");
                  LOGGER.debug("", ex);
              }
              releaseResources();
              connectionFactory.cleanup();
          }
      }
docs: Closes the database connection. Close should be called on this object
  when it is done being used.