question: public static boolean checkCommunicationError ( Exception exc ) { Throwable rootCause = SolrException . getRootCause ( exc ) ; boolean wasCommError = ( rootCause instanceof ConnectException || rootCause instanceof ConnectTimeoutException || rootCause instanceof NoHttpResponseException || rootCause instanceof SocketException ) ; return wasCommError ; }
target:  Determine if a request to Solr failed due to a communication error, which is generally retry-able. 