0 Replies Latest reply on Apr 8, 2012 11:35 AM by helga.w.

End-of life issues for Stateful Session Beans

helga.w. Apr 8, 2012 11:35 AM

I am in the progress of migrating an application from jBoss 4.x to jBoss 7.1

One of the issues I am having is that I am unsure if stateful session beans are destroyed in an orderly fashion. Specifically, it seems to me that I can't access member variables from a method annotated with @PreDestroy.

This is the example that I have created to reproduce this:

I have a session bean with a livespan of 1 minute. When it is destroyed, it should do some cleanup (most notably I need to inform a remote API that some limited resources can be released).

I log the entry into the @PostDestroy method, but whenever I try to access a member variable (even just to log the value), nothing happens, and all further logs are not printed, so it looks like the cleanup thread just hangs.

On the client side I have some test code that creates the bean, sleeps for 2 minutes (to make sure the session bean is dead) and then try to access the (now assumed dead) session bean. I get a notification from jBoss "ERROR [org.jboss.as.ejb3.component.interceptors.LoggingInterceptor.processInvocation(LoggingInterceptor.java:66)] (ajp --127.0.0.1-8009-4) JBAS014134: EJB Invocation failed on component TestBean for method public abstract Error com.acme.Test.getLastMessage(): javax.ejb.NoSuchEJBException: Could not find SFSB TestBean with {[-49, 41, -116, -64, 26, -7, 65, 92, -87, 58, 123, 91, -88, 4, -77, 55]}"

This happens even though the the method call is wrapped in a try/catch to handle NoSuchEJBException.

So the questions I have are the following

What am I doing wrong? This worked fine in 4.2.x
Should I assume that the bean is already dead in @PreDestroy? If so, when should I do my cleanup?
Am I accumulating an army of zombie TestBeans, stuck between the world of the living and the dead?
What is the meaning of the Stack dump EJB Invocation failed on component... Why is it logged even though I am handling this exception in my code?

I am using jBoss AS 7.1.1 (jboss-as-7.1.1.Final)

Here is the relevant code

The session bean

@Stateful

@TransactionManagement

@StatefulTimeout(unit = TimeUnit.MINUTES, value = 1)

public class TestBean implements Test, TestLocal

{

@PersistenceContext(unitName = "userPU")

private EntityManager emUser;

private static final Logger logger = Logger.getLogger(TapBean.class);

private UUID uuid;

private DateTime liveSince;

// other stuff

public TestBean()

{

logger.info ("Creating a new instance of Test");

uuid = UUID.randomUUID();

liveSince = new DateTime();

}

@PrePassivate

public void passivate()

{

logger.info("passivating");

// never called

}

@PreDestroy

public void destroy()

{

DateTime now = new DateTime();

logger.info("destroying "); // this I see

cleanup();

logger.info("destroy took " + new Duration(now, new DateTime())); // this is never logged

}

@Remove

public void remove()

{

logger.info("timeout");

// never called

}

public void cleanup()

{

logger.info("Passivating '" + uuid + "' after " + new Duration(liveSince, new DateTime()).getStandardMinutes()); // never logged

// notify remote API to release resources

}

The web side code:

Test mySFSB = (Test) session.getAttribute("Test");

Error error = null;

logger.info("sleeping");

Thread.sleep(2*60000L);

logger.info("done sleeping");

try

{

logger.info("About to get last message" );

error = mySFSB.getLastMessage();

logger.info("done getting last message" );

}

catch (NoSuchEJBException e)

{

logger.error("Caught NoSuchEJBException " + e.getMessage());

}

catch (Exception e)

{

logger.error("Got " + e.getMessage());

}

Here is a log:

13:53:50,834 INFO [com.acme.server.TestBean.<init>(TestBean.java:140)] (ajp--127.0.0.1-8009-4) Creating a new instance of Test

.... do some server stuff

13:54:06,731 INFO [com.acme.web.PageAction.execute(PageAction.java:266)] (ajp--127.0.0.1-8009-4) sleeping

13:54:55,740 INFO [com.acme.server.TestBean.destroy(TestBean.java:158)] (pool-19-thread-1) destroying

// notice lack of a log message from the method cleanup()

13:56:06,730 INFO [com.acme.web.PageAction.execute(PageAction.java:268)] (ajp--127.0.0.1-8009-4) done sleeping

13:58:50,243 INFO [com.acme.web.PageAction.execute(PageAction.java:271)] (ajp--127.0.0.1-8009-4) About to get last message

// Here we know mySFSB is dead, but we think we are handling this gracefully

// Annoying ERROR log from jBoss, the meaning of which is not clear

13:58:50,246 ERROR [org.jboss.as.ejb3.component.interceptors.LoggingInterceptor.processInvocation(LoggingInterceptor.java:66)] (ajp--127.0.0.1-8009-4) JBAS014134: EJB Invocation failed on component TestBean for method public abstract com.acme.server.data.TestError com.acme.server.Test.getLastMessage(): javax.ejb.NoSuchEJBException: Could not find SFSB TestBean with {[-49, 41, -116, -64, 26, -7, 65, 92, -87, 58, 123, 91, -88, 4, -77, 55]}

at org.jboss.as.ejb3.component.stateful.StatefulComponentInstanceInterceptor.processInvocation(StatefulComponentInstanceInterceptor.java:62) [jboss-as-ejb3-7.1.1.Final.jar:7.1.1.Final]