question: public void shutdown ( ) throws MessageServiceException { LOGGER . warn ( "Shutdown Signal Received. Shutting down." ) ; m_shutdown . set ( true ) ; Request shutdownRequest = new AbortRequest ( ) ; m_requestQueue . offer ( shutdownRequest ) ; while ( m_requestQueue . size ( ) != 0 ) { try { Thread . sleep ( 100 ) ; } catch ( InterruptedException e ) { LOGGER . error ( "Exception while draining requests from queue" , e ) ; } } closeConnection ( ) ; if ( pingerTask != null ) pingerTask . cancel ( ) ; boolean status = Management . removeBeanOrFolder ( "MessageService/Transport/ZooKeeper/context/" + m_context + "/stats" ) ; if ( status ) LOGGER . info ( "stop monitoring MessageService/Transport/ZooKeeper/context/" + m_context + "/stats" ) ; status = Management . removeBeanOrFolder ( "MessageService/Transport/ZooKeeper/context/" + m_context + "/registry" ) ; if ( status ) LOGGER . info ( "stop monitoring MessageService/Transport/ZooKeeper/context/" + m_context + "/registry" ) ; }
target:  Upon shutdown signal, close the connection to ZooKeeper and come out