JMS - Using Topics on WebSphere Application Server 7 -

i have sender , receiver particular topic. i'm running sender , receiver servlets on 7.0. topic , topic connection factory being setup on was. i'm not able receive message send. works fine when try queue instead of topic.

below code use.

public class commonservlet extends httpservlet{      private static final long serialversionuid = 1l;     private static boolean initialized = false;     private static initialcontext initialcontext = null;     private connectionfactory connectionfactory = null;     private destination destination = null;      protected final void initialize(){         try{             if( initialized == false ){                 // jndi initial context                 initialcontext = new initialcontext();                  // flag initialized                 initialized = true;             }         }         catch( throwable t ){             system.out.println( t.getmessage() );         }     }      /**      * @return      */     protected final destination getdestination(){         if( destination != null ){             return destination;         }          try{             destination = (destination) initialcontext.lookup("jms/testtopic" );         }         catch( namingexception e ){             // todo auto-generated catch block             e.printstacktrace();         }         return destination;     }      /**      * @return      */     protected final connectionfactory getconnectionfactory(){         try{             connectionfactory = (connectionfactory) initialcontext.lookup("jms/testtopiccf" );         }         catch( namingexception e ){             e.printstacktrace();         }         return connectionfactory;     } } 

sender servlet class

public class sender extends commonservlet{      private static final long serialversionuid = 1l;      @override     protected void doget( httpservletrequest req, httpservletresponse resp ) throws servletexception, ioexception{         system.out.println("inside of sender");         dopost( req, resp );     }      @override     protected void dopost( httpservletrequest req, httpservletresponse resp ) throws servletexception, ioexception{         string message = req.getparameter( "message" );         sendmessage( message );     }      private void sendmessage( string messagetext ){         initialize();         try{             connectionfactory factory = getconnectionfactory();              destination destination = getdestination();              connection connection = factory.createconnection();             connection.start();              session session = connection.createsession( false, session.auto_acknowledge );              messageproducer sender = session.createproducer( destination );              textmessage txtmsg = session.createtextmessage( messagetext );              sender.send( txtmsg );         }         catch( exception ex ){             ex.printstacktrace();         }     } } 

receiver servlet class

public class receiver extends commonservlet{      private static final long serialversionuid = 1l;       @override     protected void doget( httpservletrequest req, httpservletresponse resp ) throws servletexception, ioexception{         dopost( req, resp );     }      @override     protected void dopost( httpservletrequest req, httpservletresponse resp ) throws servletexception, ioexception{         getmessage();     }      private void getmessage(){         initialize();         connectionfactory factory = getconnectionfactory();          destination destination = getdestination();          try{             connection connection = factory.createconnection();              connection.start();              session session = connection.createsession( false, session.auto_acknowledge );              messageconsumer receiver = session.createconsumer( destination );              message message = receiver.receive( 4000 );              system.out.println( message );//coming null         }         catch( jmsexception e ){             e.printstacktrace();         }      }  } 

both testtopic , testtopiccf configured in administration console under resources > jms > topic connection factory , topics section. there no exceptions while running application. works fine if use queue , queue connection factory created. there need topic working?

topics different destinations queues, default not persist messages , subscriber has connected, when publisher sends message. see details here

publishers , subscribers have timing dependency. client subscribes topic can consume messages published after client has created subscription, , subscriber must continue active in order consume messages.

so in short:

• your current design not correct topics, have first call receiver servlet, have there long receive timeout, , in second window try sender servlet, message lost.
• much better approach use mdb message receiver instead of servlet
• if need receive messages sends topic while subscriber inactive, need configure durable subscriber , configure topic durable in was.