activemq-dev mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From "Timothy Bish (Commented) (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (AMQ-3760) Deadlock on Java Client when onMessage executes a synchronized method.
Date Wed, 07 Mar 2012 21:06:57 GMT

    [ https://issues.apache.org/jira/browse/AMQ-3760?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=13224707#comment-13224707
] 

Timothy Bish commented on AMQ-3760:
-----------------------------------

This sort of use of sessions, producers and consumers is discouraged by the spec:

"If a client desires to have one thread produce messages while others consume them, the client
should use a separate session for its producing thread.

Once a connection has been started, any session with one or more registered message listeners
is dedicated to the thread of control that delivers messages to it. It is erroneous for client
code to use this session or any of its constituent objects from another thread of control.
The only exception to this rule is the use of the session or connection close method. "

                
> Deadlock on Java Client when onMessage executes a synchronized method.
> ----------------------------------------------------------------------
>
>                 Key: AMQ-3760
>                 URL: https://issues.apache.org/jira/browse/AMQ-3760
>             Project: ActiveMQ
>          Issue Type: Bug
>          Components: JMS client
>    Affects Versions: 5.5.1
>         Environment: java version "1.6.0_30"
> Java(TM) SE Runtime Environment (build 1.6.0_30-b12)
> Java HotSpot(TM) Server VM (build 20.5-b03, mixed mode)
> OS: SunOs 10/06
>            Reporter: Alessandro Monguzzi
>              Labels: features
>         Attachments: ActiveMQDeadlock.zip
>
>
> Create a class with two synchronized methods synchMethod1 and synchMethod2. 
> syncMethod1 is invoked inside a messageListener object and only prints a message on stdout.
> syncMethod2 creates a new MessageConsumer with a new instance of MessageListener. All
the MessageConsumers created by synchMethod2 share the same session.
> All the consumers listen on the same Topic named "myDest".
> Create an infinite cycle that: 
> 1) send a message on Topic "myDest"
> 2) invoke syncMethod2
> 3) waits 10ms
> In attach the unit test source.
> As result, a deadlock is created between the "ActiveMQ Session Task" thread entering
in syncMethod1 having the ActiveMessageConsumer's mutex and my other thread executing the
syncMethod2 when the SimplePriorityMessageDispatchChannel.stop() method is invoked.
> This means that it's not possible to create or change MessageListeners on a running session,
even if the code seems to handle this case stopping and restarting the session.

--
This message is automatically generated by JIRA.
If you think it was sent incorrectly, please contact your JIRA administrators: https://issues.apache.org/jira/secure/ContactAdministrators!default.jspa
For more information on JIRA, see: http://www.atlassian.com/software/jira

        

Mime
View raw message