question: public Requestor ( String [ ] groups , int port , boolean delayFlag ) throws IOException { super ( "GS-multicast-discovery-request" ) ; setDaemon ( true ) ; sock = new MulticastSocket ( Constants . getDiscoveryPort ( ) ) ; sock . setTimeToLive ( multicastRequestConstraints . getMulticastTimeToLive ( Constants . getTtl ( ) ) ) ; responsePort = port ; this . groups = groups == null ? new String [ 0 ] : groups ; this . delayFlag = delayFlag ; }
target:  Create a daemon thread