for(int i=1; i< 500000; i++) {
   System.out.println("Starting process " + i);

   // get the UserTransaction and EJB Proxy
   Context ctx = getInitialContext(host, port, username, password);
   UserTransaction tx = getUserTransaction(ctx);
   ControllerRemote cr = (ControllerRemote)
  ctx.lookup("Controller/Controller" + "!com.test.usertransaction.ControllerRemote");

   try {
     tx.begin();
   }
   catch(Exception ex1) {
     ex1.printStackTrace();
   }
   //System.out.println("user transaction started");

   cr.mainCall();

   try {
     tx.commit();;
   }
   catch(Exception ex1) {
     ex1.printStackTrace();
     throw ex1;
   }
   //System.out.println("commited user transaction");

   if(ctx != null)
     ctx.close();
 }