web-services singleton glassfish lifecycle

Can I have a singleton lifecycle webservice on glassfish V3?

I have a simple webservice created with Netbeans 6.5 and deployed into 2 glassfish servers V2.1 and V3. The ws has a basic method GetInstanceID that I call 3 times from a client.

@WebService()
public class FirstWS {

private long m_instanceID = 0;   //instance id

//Log
private void WriteLog(String cadena){
    String msg = "";
    DateFormat dateFormat = new SimpleDateFormat("dd/MM/yyyy HH:mm:ss:SSS");
    Date fecha = new Date();
    msg = dateFormat.format(fecha) + " ***** " + this.getClass().getName() + " (m_instanceID=" + m_instanceID + "): " + cadena +
          "           " + "ThreadID=" + Thread.currentThread().getId() + " ThreadName=" + Thread.currentThread().getName();
    Logger.getLogger(this.getClass().getName()).log(Level.INFO,msg);
}

//Constructor
public FirstWS() {
    Random rnd = new Random();
    m_instanceID = rnd.nextLong();
    WriteLog("Executing Constructor");
}

//PostConstruct
@PostConstruct
public void ThisIsThePostConstruct() {
    WriteLog("Executing PostConstruct");
}

//PreDestroy
@PreDestroy
public void ThisIsThePreDestroy() {
    WriteLog("Executing PreDestroy");
}

//Method
@WebMethod(operationName = "GetInstanceID")
@WebResult(name="InstanceID")
public long GetInstanceID() {
    //TODO write your implementation code here:
    WriteLog("Executing GetInstanceID");
    return m_instanceID;
}

}

I always though that web services were singleton by default.

On the glassfish V2.1 server the ws is working as expected, with a singleton lifecycle:

Only one instance is created.
Only one execution of constructor method.
Only one execution if postconstructor method.
Only one execution of predestroy method when ws is undeployed.

Client log

InstanceID = -4747957096764272596

Server log

26/08/2010 13:08:15:146 ***** first.test.FirstWS (m_instanceID=-4747957096764272596): Executing Constructor ThreadID=68 ThreadName=httpSSLWorkerThread-8080-0

26/08/2010 13:08:15:161 ***** first.test.FirstWS (m_instanceID=-4747957096764272596): Executing PostConstruct ThreadID=68 ThreadName=httpSSLWorkerThread-8080-0

26/08/2010 13:08:15:364 ***** first.test.FirstWS (m_instanceID=-4747957096764272596): Executing GetInstanceID ThreadID=69 ThreadName=httpSSLWorkerThread-8080-1

26/08/2010 13:08:15:380 ***** first.test.FirstWS (m_instanceID=-4747957096764272596): Executing GetInstanceID ThreadID=69 ThreadName=httpSSLWorkerThread-8080-1

26/08/2010 13:08:15:396 ***** first.test.FirstWS (m_instanceID=-4747957096764272596): Executing GetInstanceID ThreadID=69 ThreadName=httpSSLWorkerThread-8080-1

26/08/2010 13:08:38:849 ***** first.test.FirstWS (m_instanceID=-4747957096764272596): Executing PreDestroy ThreadID=626 ThreadName=Thread-540

But on the glassfish V3 server the ws isn't working as expected, because a new instance of the ws is created for EVERY call to the GetInstanceID:

One instance is created for every call.
One execution of constructor method for every call.
Two (!?!?!) executions of postconstructor method for every call.
The predestroy method isn't called when ws is undeployed.

Client log

InstanceId = 7754248300017958713

InstanceId = -1714184485890589231

InstanceId = -4156829683887899017

Server log

INFO: 26/08/2010 15:16:11:429 ***** first.test.FirstWS (m_instanceID=7754248300017958713): Executing Constructor ThreadID=103 ThreadName=http-thread-pool-8080-(2)

INFO: 26/08/2010 15:16:11:429 ***** first.test.FirstWS (m_instanceID=7754248300017958713): Executing PostConstruct ThreadID=103 ThreadName=http-thread-pool-8080-(2)

INFO: 26/08/2010 15:16:12:429 ***** first.test.FirstWS (m_instanceID=7754248300017958713): Executing GetInstanceID ThreadID=103 ThreadName=http-thread-pool-8080-(2)

INFO: 26/08/2010 15:16:12:460 ***** first.test.FirstWS (m_instanceID=-1714184485890589231): Executing Constructor ThreadID=102 ThreadName=http-thread-pool-8080-(1)

INFO: 26/08/2010 15:16:13:429 ***** first.test.FirstWS (m_instanceID=-1714184485890589231): Executing PostConstruct ThreadID=102 ThreadName=http-thread-pool-8080-(1)

INFO: 26/08/2010 15:16:14:429 ***** first.test.FirstWS (m_instanceID=-1714184485890589231): Executing GetInstanceID ThreadID=102 ThreadName=http-thread-pool-8080-(1)

INFO: 26/08/2010 15:16:14:445 ***** first.test.FirstWS (m_instanceID=-4156829683887899017): Executing Constructor ThreadID=103 ThreadName=http-thread-pool-8080-(2)

INFO: 26/08/2010 15:16:15:429 ***** first.test.FirstWS (m_instanceID=-4156829683887899017): Executing PostConstruct ThreadID=103 ThreadName=http-thread-pool-8080-(2)

INFO: 26/08/2010 15:16:15:429 ***** first.test.FirstWS (m_instanceID=-4156829683887899017): Executing GetInstanceID ThreadID=103 ThreadName=http-thread-pool-8080-(2)

INFO: Closing Metro monitoring root: amx:pp=/mon/server-mon[server],type=WSEndpoint,name=/FirstWebApplication-FirstWSService-FirstWSPort

So, why this behaviour on glassfish V3? How could I have a singleton web service on glassfish V3?

Solution

Finally I found the problem: the type of the project. In NetBeans I created the web service in a "Web Aplication" project so it was deployed into a servlet container in Glassfish and @Stateless and @Singleton annotations don't work. You must create the ws in a "EJB Moule" project and it will be deployed into a EJB container so @Stateless and @Singleton annotations work correctly.

As Java EE 6 says "Singleton session beans offer similar functionality to stateless session beans but differ from them in that there is only one singleton session bean per application, as opposed to a pool of stateless session beans, any of which may respond to a client request. Like stateless session beans, singleton session beans can implement web service endpoints."