rosjava communication exception: org.ros.exception.RosRuntimeException: Connection exception

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Hi everyone, I'm new in rosjava. I'am now wrtting a subscriber in rosjava in rosjava node named mynode to "reveive" message type sensor_msgs/JointState from a publisher named /joint_states written in C++. The registering process was ok but there was an exception like the following:

Jul 20, 2012 4:12:50 PM org.ros.internal.node.client.Registrar callMaster
INFO: Response<Success, Registered [/mynode] as publisher of [/rosout], [http://auburn:46838/]>
Jul 20, 2012 4:12:50 PM org.ros.internal.node.topic.DefaultPublisher$1 onMasterRegistrationSuccess
INFO: Publisher registered: Publisher<PublisherDefinition<PublisherIdentifier<NodeIdentifier</mynode, http://127.0.0.1:33391/>, TopicIdentifier</rosout>>, Topic<TopicIdentifier</rosout>, TopicDescription<rosgraph_msgs/Log, acffd30cd6b6de30f120938c17c593fb>>>>
Jul 20, 2012 4:12:50 PM org.ros.internal.node.client.Registrar onSubscriberAdded
INFO: Registering subscriber: Subscriber<Topic<TopicIdentifier</joint_states>, TopicDescription<sensor_msgs/JointState, 3066dcd76a6cfaef579bd0f34173e9fd>>>
Jul 20, 2012 4:12:50 PM org.ros.internal.node.client.Registrar callMaster
INFO: Response<Success, Subscribed to [/joint_states], [http://auburn:56996/, http://auburn:41568/]>
Jul 20, 2012 4:12:50 PM org.ros.internal.node.topic.DefaultSubscriber$1 onMasterRegistrationSuccess
INFO: Subscriber registered: Subscriber<Topic<TopicIdentifier</joint_states>, TopicDescription<sensor_msgs/JointState, 3066dcd76a6cfaef579bd0f34173e9fd>>>
Jul 20, 2012 4:13:01 PM org.ros.internal.node.topic.UpdatePublisherRunnable run
SEVERE: org.ros.exception.RosRuntimeException: Connection exception: auburn/194.199.21.22:32880
Jul 20, 2012 4:13:01 PM org.ros.internal.transport.ConnectionTrackingHandler exceptionCaught
SEVERE: Channel exception: java.net.ConnectException: connection timed out
Jul 20, 2012 4:13:11 PM org.ros.internal.node.topic.UpdatePublisherRunnable run
SEVERE: org.ros.exception.RosRuntimeException: Connection exception: auburn/194.199.21.22:46961
Jul 20, 2012 4:13:11 PM org.ros.internal.transport.ConnectionTrackingHandler exceptionCaught
SEVERE: Channel exception: java.net.ConnectException: connection timed out
Jul 20, 2012 4:13:12 PM org.ros.internal.transport.ConnectionTrackingHandler exceptionCaught

**I wonder that why the subscribing process was ok while the message receiving was corrupted by an exception ? In the exception message below i saw an ip 194.199.21.22. This i not my computer ip address. Moreover the rosjava node ran on http://127.0.0.1:port but the roscore and other node in C++ ran on http://auburn:ports (auburn: name of my computer).

Everything was ok if i used a subscriber in C++.**

Thank,