Re: TCPSession.sendFrame: NullPointerException

I haven't seen much traffic on this list since I joined. It's good to 
see some.

I found a bug in Java BEEP and reported it to the buglist at the BEEP
SourceForge site.  I just wonder - is that the right thing to do, or are 
other
users using this list to talk about bugs?

-- Pete

Wladimir Araujo wrote:
> I've run into this a couple of times. TCPSession has some race
> conditions re the socket manipulation. What I do to avoid these problems
> (all but one) is to guarantee that the channel and session cannot be
> closed while sending messages (through external locks). Of course, if
> the session is closed from the other side there is nothing we can do. In
> this case, the NullPointerException kills the TCPSEssion thread (created
> inside enableIO()).
>
> Fixing these problems is not trivial (chance of distributed deadlock),
> so I decided it was easier to live with them ;-)
>
> Wladimir 
> -----Original Message-----
> From: [email protected]
> [mailto:[email protected]] On Behalf Of
> Lukas Zbinden
> Sent: Monday, December 05, 2005 6:21 AM
> To: [email protected]
> Subject: [Beepcore-java-users] TCPSession.sendFrame:
> NullPointerException
>
> Hi
>
> We use the beepcore java library in our diploma project 'a  
> collaborative editor'.
> When two users collaboratively edit a document, each character is sent  
> over a channel by a call to
> myChannelImplInstance.sendMSG(outputData, myReplylistener).
> Both sides use the same channel. After a while (both users type very  
> fast, i.e.
> channel.sendMSG(..) is called at a high rate), the following exception  
> occurs:
>
> Caused by: java.lang.NullPointerException
>          at  
> org.beepcore.beep.transport.tcp.TCPSession.sendFrame(TCPSession.java: 
> 291)
>          at  
> org.beepcore.beep.core.ChannelImpl.sendFrames(ChannelImpl.java:837)
>          at  
> org.beepcore.beep.core.ChannelImpl.sendQueuedMessages(ChannelImpl.java: 
> 773)
>          at  
> org.beepcore.beep.core.ChannelImpl.sendToPeer(ChannelImpl.java:754)
>          at  
> org.beepcore.beep.core.ChannelImpl.sendMSG(ChannelImpl.java:414)
>          at  
> ch.iserver.ace.net.impl.protocol.AbstractConnection.send(AbstractConnect
>
> ion.java:77)
>          at  
> ch.iserver.ace.net.impl.protocol.ParticipantConnectionImpl.sendToPeer(Pa
>
> rticipantConnectionImpl.java:261)
>          at  
> ch.iserver.ace.net.impl.protocol.ParticipantConnectionImpl.sendRequest(P
>
> articipantConnectionImpl.java:157)
>          at  
> ch.iserver.ace.collaboration.jupiter.server.ParticipantConnectionWrapper
>
> .sendRequest(ParticipantConnectionWrapper.java:177)
>          at sun.reflect.GeneratedMethodAccessor17.invoke(Unknown Source)
>          at  
> sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessor
>
> Impl.java:25)
>          at java.lang.reflect.Method.invoke(Method.java:324)
>          at  
> org.springframework.aop.support.AopUtils.invokeJoinpointUsingReflection(
>
> AopUtils.java:335)
>          at  
> org.springframework.aop.framework.ReflectiveMethodInvocation.invokeJoinp
>
> oint(ReflectiveMethodInvocation.java:181)
>          at  
> org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(Ref
>
> lectiveMethodInvocation.java:148)
>          at  
> ch.iserver.ace.util.AsyncMethodInvocation.proceed(AsyncMethodInvocation.
>
> java:100)
>          at ch.iserver.ace.util.AsyncWorker.doWork(AsyncWorker.java:102)
>          at ch.iserver.ace.util.Worker.run(Worker.java:49)
>
>
> Does anyone know this problem? Is it a bug or do I use the channel the  
> wrong way?
>
> Any help highly appreciated.
>
> Lukas
>
>
>
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