question: private JMXConnector connect ( String host , int port ) { try { if ( ! isNodeAvailable ( host ) ) { log . info ( "Node({}) is unavailable" , host ) ; throw new IllegalStateException ( "Node is unavailable" ) ; } log . debug ( "Connecting to JMX Server {}:{}" , host , port ) ; String connectorAddress = String . format ( serviceUrl , host , port ) ; JMXServiceURL jmxUrl = new JMXServiceURL ( connectorAddress ) ; return JMXConnectorFactory . connect ( jmxUrl ) ; } catch ( MalformedURLException e ) { log . error ( String . format ( "Failed to construct jmx url for %s:%d" , host , port ) , e ) ; throw new IllegalStateException ( "Failed to construct jmx url" ) ; } catch ( IOException e ) { log . error ( String . format ( "Failed to connect %s:%d" , host , port ) , e ) ; throw new IllegalStateException ( "Failed to connect " + host ) ; } }
target:  Create a connection to the JMX agent