[jboss-jira] [JBoss JIRA] Assigned: (JGRP-446) When using an extremely simple protocol stack the app will respond with a NullPointerException.

[Bela Ban (JIRA)]

     [ http://jira.jboss.com/jira/browse/JGRP-446?page=all ]

Bela Ban reassigned JGRP-446:
-----------------------------

    Assignee: Vladimir Blagojevic  (was: Bela Ban)

This is a somewhat unusual stack, but let's fix this by possibly adding a null-check before generating the view

> When using an extremely simple protocol stack the app will respond with a NullPointerException.
> -----------------------------------------------------------------------------------------------
>
>                 Key: JGRP-446
>                 URL: http://jira.jboss.com/jira/browse/JGRP-446
>             Project: JGroups
>          Issue Type: Bug
>    Affects Versions: 2.4.1 SP1
>         Environment: Windows XP
> java version "1.5.0_11"
> Java(TM) 2 Runtime Environment, Standard Edition (build 1.5.0_11-b03)
> Java HotSpot(TM) Client VM (build 1.5.0_11-b03, mixed mode)
>            Reporter: Anders Persson
>         Assigned To: Vladimir Blagojevic
>            Priority: Minor
>
> When using an extremely simple protocol stack the app will respond with a NullPointerException. The communication will however work (at least when running all parties on the same machine). The stack used:
> <protocol_stacks>
>   <stack name="standard" description="Multicast stack intended for usage on internal highspeed networks.">
>     <config>
>       <UDP mcast_addr="228.15.15.15"
>             mcast_port="45566"/>
>       <PING timeout="2000"/>
>     </config>
>   </stack>
>   <stack name="slow" description="Multicast stack intended for usage on external slow connections.">
>     <config>
>       <UDP mcast_addr="228.15.15.15"
>             mcast_port="45567"/>
>       <PING timeout="2000"/>
>     </config>
>   </stack>
> </protocol_stacks>
> Starting DrawMultiplexer using the stack above will generate the following stack trace
> 2007-mar-26 16:51:24 org.jgroups.JChannelFactory connect
> SEVERE: failed sending SERVICE_UP message
> java.lang.NullPointerException
>         at org.jgroups.mux.Multiplexer.generateServiceView(Multiplexer.java:953)
>         at org.jgroups.mux.Multiplexer.handleServiceUp(Multiplexer.java:781)
>         at org.jgroups.mux.Multiplexer.sendServiceUpMessage(Multiplexer.java:224)
>         at org.jgroups.JChannelFactory.connect(JChannelFactory.java:372)
>         at org.jgroups.mux.MuxChannel.connect(MuxChannel.java:126)
>         at org.jgroups.demos.DrawMultiplexer.start(DrawMultiplexer.java:44)
>         at org.jgroups.demos.DrawMultiplexer.main(DrawMultiplexer.java:29)
> I traced the "problem" to be the lack of a pbcast.GMS entry. (You can try it by removing that entry in the conf/stacks.xml file in your distribution.)
> Some additional information:
> In order to get DrawMultiplexer to "communicate" you will have to start two instances using the stack above. Then press "leave" in the window that pops up as a result of the FIRST instance started. (Don't know the inner workings of the DrawMultiplexer app, I don't have to resort to these kinds of actions to get my own app to communicate.)
> The reason I would like to see this fixed is that I don't want to have NullPointerExceptions in the log file when deploying this at the customer.
> The reason for my very simple protocol is that we intend to use JGroups in a configuration where one server pumps out data in a stream to a varying number of clients and we don't care if the data was received correctly or not since the stream of data is repeated every six seconds.

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