What's wrong to put Thread.sleep in a session bean?

i am working on a trading platform and i think there is a design flaw. The part i am working on is the Order Management module. When an order value object is published to a JMS topic and picked up by a MDB. The MDB, in turn, calls a session bean (could be stateless, I didn't check), OrderEngineBean. After this bean saves the order vo into database and broadcast the message to all involved parties, it suspends for 12 sec, using Thread.sleep, so other parities might have a chance to update the vo. If no update occurs, the order is considered expired and abandoned.
It looks awkward to me to use a Thread.sleep in a session, but I haven't come out with a better idea to deal with the scenario like above.
Anyone can help me out?
Thanks a lot!
Sway

Setting the property "max-beans-in-free-pool" is not the answer to this issue. By setting this property to 1, the container merely instantiates and keeps one instance of the bean in the free pool at the "start" of the app server. But if the container comes across more than one requests for the same EJB simultaneoulsy, then it will create new instances at that time to handle the requests simultaneously.
You are seeing intermixed log messages between two threads because these messages are being logged from two different instances of the EJB and NOT the same instance of the EJB. The container does synchronizes the calls on "a method" on "a instance". So what you are seeing are the messages coming from "a method" on "two different instances" of the same EJB.
You can refer to the EJB 2.0 specification section 6.11.6 Non-reentrant instances for details about simultaneous access to the same session object.

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watwatacrazy wrote:
What is an alternate to thread.sleep? The reason being, my action listener won't let me throw exceptions so I need an alternative to thread.sleep, anything?I am in no way condoning this idea, because as mentioned it is a very bad idea.
However. Not lettiing you throw exceptions is not a reason to not do something. All it means is that you need a catch block. You should review the exceptions part of the Java tutorial found here [_Java Tutorial : Exceptions_|http://java.sun.com/docs/books/tutorial/essential/exceptions/index.html]

OrionRemoteException: Second thread call to stateful session bean

What happen for "com.evermind.server.rmi.OrionRemoteException: Second thread call to stateful session bean".
I am using JSP/Servlet/EJB and OC4J. When user click the JSP page button to fast, sometimes the error will appear, and then the OC4J will stop, I need to restart the OC4J.
I am using standlone OC4J 9.0.3.0.0
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Have you cached the remote object you obtained for the stateful session beamn and are reusing the same object on subsequent requests from the JSP page? So in effect, you are making a second call to the bean before the first method call completes?
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1) Second thread call to stateful session bean.

Hi Friend,
I read your threads on otn and i compared your problem with us and i analysed that your application and my application is same, So Plese can you help me in some issues.
Friend, Please help me in these issues, Thanks for this
We have very big ADF Swing+BC Application and deployed as Stateful Session Bean. in my application there are 500 Application Modules,For each application module i created Stateful session beans and deployed it on OC4J Container but when working on deployed application then i am getting time out error after 15 min of working.
1). I set that parameter that you mentioned i.e jbo.ejb.txntimeout = 86400,but still it is giving me same error.
2). Second Issue is of ---ORA-01000: maximum open cursors exceeded
For this issue i chaged the Database Parameter i.e OpenCurser=2000, but still it is giving me same error,
is there any parameter on application module required to change so that this error will not come.
3). When i close the form then application module is not releasing database connection.
4). (oracle.oc4j.rmi.OracleRemoteException) Second thread call to stateful session bean
This error is also coming when I am using deployed application for long time i.e more than 15 min for Heavy Transactions

Hi Suyog,
How r u?
We all are fine.
I alerady tried for the Max Curser Property but it is not helpfull.
I think again i have to go for closing opened db RS and statements.
Thanks
Vijay

Spawning thread in the stateful session bean

I ran into an interesting issue: I am spawning a thread inside
my stateful session bean's ejbCreate(...) method. The spawned
thread runs in an infinite loop until some stop signal. The
thread uses some BMP entity beans to access some data from DB,
it creates some BMP entity beans as well as creates another
stateful session bean in each iteration. The application ran
into a crash. Now I have a couple questions:
- First, is it an allowed operation to have a stateful session
bean spawn off threads? Am I violating the specs?
- Second, is it also allowed to have that thread create another
bmp entity bean and another stateful session bean? Again, am I
violating the specs also in here?
Your responses will be very much appreciated.
- Simon

From the EJB 2.0 Spec, Section 24.1.2:
<quote>
These networking functions are reserved for the EJB Container.
Allowing the enterprise bean to use these functions could compromise
security and decrease the Container’s ability to properly manage the
runtime environment.
• The enterprise bean must not attempt to manage threads. The
enterprise bean must not attempt to start, stop, suspend, or resume
a thread; or to change a thread’s priority or name. The enter-prise
bean must not attempt to manage thread groups.
<quote>
And, spawning threads in weblogic is highly discouraged in any
server-side component. An application should not be designed this
way.
Bill
Simon wrote:
I ran into an interesting issue: I am spawning a thread inside
my stateful session bean's ejbCreate(...) method. The spawned
thread runs in an infinite loop until some stop signal. The
thread uses some BMP entity beans to access some data from DB,
it creates some BMP entity beans as well as creates another
stateful session bean in each iteration. The application ran
into a crash. Now I have a couple questions:
- First, is it an allowed operation to have a stateful session
bean spawn off threads? Am I violating the specs?
- Second, is it also allowed to have that thread create another
bmp entity bean and another stateful session bean? Again, am I
violating the specs also in here?
Your responses will be very much appreciated.
- Simon

What is wrong with my thread condition??

I have two kinds of threads:
1) WriterThread is cable of inserting keys with a corresonding object into a database.
2) ReaderThread which should be able to wait for a specific key is inserted into the database.
I store the key waited for by a ReaderThread and its id in a HashTable (the database is also a Hashtable).
If I have 3 ReaderThreads that is waiting (with id 1,2,3) and thread 2 is waiting for "key2", I would only have ReaderThread 2 to wake up when "key2" is inserted by a WriterThread.
Therefor I have made a condition in the "waitfor" method for the threads that is awakened (its after the first call to wait()). But it only works the first time I insert one of the keys awaited keys. The next time I insert a key all the remaining threads are reactivated!
public class DataBase extends Hashtable{
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    private Hashtable hold = new Hashtable(); // Holds the id and the key the thread is waiting for.
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        if (this.containsKey(key)){
            System.out.println("Database already contains key: \""+ key + "\".");
        else{
            if (hold.containsKey(key)){
                this.findId(hold.get(key));
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                this.put(key,o);
                notifyAll();
            else{
                this.put(key,o);
                System.out.println("Key: \"" + key +"\" inserted.");
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        this.remove(key);
        System.out.println("Key: "+"\"" + key + "\" with its corresponding value is removed from the Database." );
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        Integer thread_id = new Integer(id);
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        catch(InterruptedException e){}
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            try{
                System.out.println("Return to wait");
                wait();
            catch(InterruptedException e){}
}

Well, when it checks if the key is in the hold table, if it is then 'notifyAll()' notifies all threads!
Try this, instead if an int to identify the threads, try using a monitor, that way instead of 'notifyAll()' you could use:
((Thread)hold.get(key)).notifyAll()Then only the thread that is registered for that key get's notified.
and in the waitFor method use:
    public synchronized void waitfor(String key, Object id){
        Integer thread_id = new Integer(id);
        hold.put(key,thread_id);
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Can someone tell me what's wrong with my threading code

I got some code from a Java book on how to create a simple threading application. This is the exact code from the book but for some reason it gives me an error that non-static variables can not be referenced from static content. How can I reword this to work?
<CODE>
package multithread;
import java.io.*;
import java.util.*;
public class MultiThread {
class CountDownEven extends Thread {
public void run() {
for (int i = 6; i > 0; i -= 2) {
System.out.println(this.getName() + " Count" + i);
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class CountDownOdd extends Thread {
public void run() {
for (int i = 5; i > 0; i -= 2) {
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CountDownEven count1 = new CountDownEven();
CountDownOdd count2 = new CountDownOdd();
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One possible solution:public static void main(String[] args) {
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Second thread call to stateful session bean

Hi,
My application runs on 9.0.3 and works fine.
I am migrating my application from OC4J 9.0.3 to OC4J 9.0.4.
Anyone knows anything about this error ? I don't understand where is the problem.
Thanks.
Bye

Hello,
I work with Chris and this is one of the stacktraces we get while running two clients. I say "one of" because sometimes I get another one too, with the description "No Active transaction".
When there is only a single client, the client program runs OK, but when there are more than one client, one of them aborts with an error.
The pseudo-code, as Chris said, is:
1. getSessionContext().getUserTransaction().begin();
2. Do DB stuff (CMP, BMP etc)
3. getSessionContext().getUserTransaction().commit();
Each one theses steps is a remote call.
I tried to print the status of the transaction before the commit and it normally prints ACTIVE. But suddently after some number of runs (), the status returns NO_TRANSACTION and the program aborts.
Thank you,
JoÃ£o.
This is the stackTrace:
javax.transaction.RollbackException
     at gov.utrafe.engine.facade.ejb.TransactionFacadeBean.commit(TransactionFacadeBean.java:235)
     at TransactionFacade_StatefulSessionBeanWrapper58.commit(TransactionFacade_StatefulSessionBeanWrapper58.java:270)
     at sun.reflect.GeneratedMethodAccessor91.invoke(Unknown Source)
     at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
     at java.lang.reflect.Method.invoke(Method.java:324)
     at com.evermind.server.rmi.RMICallHandler.run(RMICallHandler.java:124)
     at com.evermind.server.rmi.RMICallHandler.run(RMICallHandler.java:48)
     at com.evermind.util.ReleasableResourcePooledExecutor$MyWorker.run(ReleasableResourcePooledExecutor.java:192)
     at java.lang.Thread.run(Thread.java:534)
Caused by: javax.transaction.RollbackException
     at com.evermind.server.ApplicationServerTransaction.commit(ApplicationServerTransaction.java:676)
     at com.evermind.server.ApplicationServerTransactionManager.commit(ApplicationServerTransactionManager.java:433)
     at gov.utrafe.engine.facade.ejb.TransactionFacadeBean.commit(TransactionFacadeBean.java:226)
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