Networked embedded brokers fail to start, nullpointerexception?

[William Blackburn]

I am using ActiveMQ 4.0.2, I am trying to learn about simple clusters  
of brokers following the examples on the web site under 'Networks of  
Brokers', my config file for node 1 of my little cluster is:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://xbean.org/schemas/spring/1.0"; xmlns:amq="http:// 
activemq.org/config/1.0">
    <amq:broker id="broker" brokerName="Titan-AMQ-C1" useJmx="true">
        <amq:persistenceAdapter>
            <amq:journaledJDBC journalLogFiles="5"  
dataDirectory="#dataDir" />
        </amq:persistenceAdapter>
        <amq:transportConnectors>
            <amq:transportConnector uri="tcp://localhost:61616" />
        </amq:transportConnectors>
        <amq:networkConnectors>
            <amq:networkConnector uri="static://(tcp://localhost: 
61617)" failover="true" />
        </amq:networkConnectors>
    </amq:broker>
</beans>
Node 2 has an identical config, excepting that the transport and  
network uris port numbers are reversed. When I start cluster node 1,  
the log fills with the following errors, the cycle of errors appears  
to repeat endlessly as it tries to reconnect, no errors are appearing  
in the log of node 2.

Thread-51 2006-10-17 11:41:14,988 INFO   
[DemandForwardingBridge:startLocalBridge] Network connection between  
vm://Titan-AMQ-C1#0 and tcp://localhost:61617(Titan-AMQ-C2) has been  
established.
ActiveMQ Transport: tcp://localhost/127.0.0.1:61617 2006-10-17  
11:41:19,780 INFO  [DemandForwardingBridge:serviceRemoteException]  
Network connection between vm://Titan-AMQ-C1#0 and tcp://localhost: 
61617 shutdown due to a remote error: java.lang.NullPointerException
Thread-53 2006-10-17 11:41:19,802 INFO   
[NetworkConnector:onServiceAdd] Establishing network connection  
between from vm://Titan-AMQ-C1?network=true to failover:(tcp:// 
localhost:61617)?maxReconnectDelay=1000
Thread-55 2006-10-17 11:41:19,873 INFO   
[DemandForwardingBridge:startLocalBridge] Network connection between  
vm://Titan-AMQ-C1#2 and tcp://localhost:61617(Titan-AMQ-C2) has been  
established.
ActiveMQ Transport: tcp://localhost/127.0.0.1:61617 2006-10-17  
11:41:19,914 INFO  [DemandForwardingBridge:serviceRemoteException]  
Network connection between vm://Titan-AMQ-C1#2 and tcp://localhost: 
61617 shutdown due to a remote error:  
javax.jms.InvalidClientIDException: Broker: Titan-AMQ-C2 - Client:  
NC_Titan-AMQ-C1_outboundTitan-AMQ-C1 already connected
ActiveMQ Task 2006-10-17 11:41:19,917 INFO   
[DemandForwardingBridge:serviceLocalException] Network connection  
between vm://Titan-AMQ-C1#2 and tcp://localhost:61617 shutdown due to  
a local error: javax.jms.InvalidClientIDException: Broker: Titan-AMQ- 
C1 - Client: NC_Titan-AMQ-C2_inboundTitan-AMQ-C1 already connected
Thread-52 2006-10-17 11:41:19,948 INFO  [TransportConnector:stop]  
Connector vm://Titan-AMQ-C1 Stopped
Thread-58 2006-10-17 11:41:24,939 INFO   
[NetworkConnector:onServiceAdd] Establishing network connection  
between from vm://Titan-AMQ-C1?network=true to failover:(tcp:// 
localhost:61617)?maxReconnectDelay=1000
Thread-58 2006-10-17 11:41:24,942 INFO  [TransportConnector:start]  
Connector vm://Titan-AMQ-C1 Started
Thread-60 2006-10-17 11:41:24,994 INFO   
[DemandForwardingBridge:startLocalBridge] Network connection between  
vm://Titan-AMQ-C1#4 and tcp://localhost:61617(Titan-AMQ-C2) has been  
established.
ActiveMQ Transport: tcp://localhost/127.0.0.1:61617 2006-10-17  
11:41:25,307 INFO  [DemandForwardingBridge:serviceRemoteException]  
Network connection between vm://Titan-AMQ-C1#4 and tcp://localhost: 
61617 shutdown due to a remote error: java.lang.NullPointerException
Thread-61 2006-10-17 11:41:25,321 INFO  [TransportConnector:stop]  
Connector vm://Titan-AMQ-C1 Stopped
Thread-62 2006-10-17 11:41:30,361 INFO   
[NetworkConnector:onServiceAdd] Establishing network connection  
between from vm://Titan-AMQ-C1?network=true to failover:(tcp:// 
localhost:61617)?maxReconnectDelay=1000
Thread-62 2006-10-17 11:41:30,364 INFO  [TransportConnector:start]  
Connector vm://Titan-AMQ-C1 Started
Thread-64 2006-10-17 11:41:30,422 INFO   
[DemandForwardingBridge:startLocalBridge] Network connection between  
vm://Titan-AMQ-C1#6 and tcp://localhost:61617(Titan-AMQ-C2) has been  
established.
ActiveMQ Transport: tcp://localhost/127.0.0.1:61617 2006-10-17  
11:41:30,774 INFO  [DemandForwardingBridge:serviceRemoteException]  
Network connection between vm://Titan-AMQ-C1#6 and tcp://localhost: 
61617 shutdown due to a remote error: java.lang.NullPointerException
Thread-65 2006-10-17 11:41:30,793 INFO  [TransportConnector:stop]  
Connector vm://Titan-AMQ-C1 Stopped
Thread-66 2006-10-17 11:41:35,808 INFO   
[NetworkConnector:onServiceAdd] Establishing network connection  
between from vm://Titan-AMQ-C1?network=true to failover:(tcp:// 
localhost:61617)?maxReconnectDelay=1000
Thread-66 2006-10-17 11:41:35,811 INFO  [TransportConnector:start]  
Connector vm://Titan-AMQ-C1 Started
Thread-68 2006-10-17 11:41:35,861 INFO   
[DemandForwardingBridge:startLocalBridge] Network connection between  
vm://Titan-AMQ-C1#8 and tcp://localhost:61617(Titan-AMQ-C2) has been  
established.
ActiveMQ Transport: tcp://localhost/127.0.0.1:61617 2006-10-17  
11:41:36,164 INFO  [DemandForwardingBridge:serviceRemoteException]  
Network connection between vm://Titan-AMQ-C1#8 and tcp://localhost: 
61617 shutdown due to a remote error: java.lang.NullPointerException
Thread-69 2006-10-17 11:41:36,186 INFO  [TransportConnector:stop]  
Connector vm://Titan-AMQ-C1 Stopped
Thread-70 2006-10-17 11:41:41,203 INFO   
[NetworkConnector:onServiceAdd] Establishing network connection  
between from vm://Titan-AMQ-C1?network=true to failover:(tcp:// 
localhost:61617)?maxReconnectDelay=1000
Thread-70 2006-10-17 11:41:41,206 INFO  [TransportConnector:start]  
Connector vm://Titan-AMQ-C1 Started
Thread-72 2006-10-17 11:41:41,299 INFO   
[DemandForwardingBridge:startLocalBridge] Network connection between  
vm://Titan-AMQ-C1#10 and tcp://localhost:61617(Titan-AMQ-C2) has been  
established.
ActiveMQ Transport: tcp://localhost/127.0.0.1:61617 2006-10-17  
11:41:41,584 INFO  [DemandForwardingBridge:serviceRemoteException]  
Network connection between vm://Titan-AMQ-C1#10 and tcp://localhost: 
61617 shutdown due to a remote error: java.lang.NullPointerException
Thread-73 2006-10-17 11:41:41,596 INFO  [TransportConnector:stop]  
Connector vm://Titan-AMQ-C1 Stopped



What is the correct way to establish a simple network of brokers  
using the 'static' uris?

Thanks

BJ