code: private void connectToCluster() {
          assert m_cluster != null;
          try {
              m_cluster.init();     // force connection and throw if unavailable
              m_session = m_cluster.connect();
              displayClusterInfo();
          } catch (Exception e) {
              m_logger.error("Could not connect to Cassandra cluster", e);
              throw new DBNotAvailableException(e);
          }
      }
docs: Attempt to connect to the given cluster and throw if it is unavailable.