org.jgroups.protocols.UDP - failed sending message to null

Question

[hannel,192.168.0.46:40014] 15:08:03,642 - ERROR - org.jgroups.protocols.UDP - failed sending message to null (61 bytes)
java.lang.Exception: dest=/225.1.2.46:30446 (64 bytes)
    at org.jgroups.protocols.UDP._send(UDP.java:333)
    at org.jgroups.protocols.UDP.sendToAllMembers(UDP.java:283)
    at org.jgroups.protocols.TP.doSend(TP.java:1327)
    at org.jgroups.protocols.TP.send(TP.java:1317)
    at org.jgroups.protocols.TP.down(TP.java:1038)
    at org.jgroups.protocols.PING.sendMcastDiscoveryRequest(PING.java:220)
    at org.jgroups.protocols.PING.sendGetMembersRequest(PING.java:214)
    at org.jgroups.protocols.Discovery$PingSenderTask$1.run(Discovery.java:385)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:417)
    at java.util.concurrent.FutureTask$Sync.innerRunAndReset(FutureTask.java:280)
    at java.util.concurrent.FutureTask.runAndReset(FutureTask.java:135)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$101(ScheduledThreadPoolExecutor.java:65)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.runPeriodic(ScheduledThreadPoolExecutor.java:142)
    at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:166)
    at java.util.concurrent.ThreadPoolExecutor$Worker.runTask(ThreadPoolExecutor.java:650)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:675)
    at java.lang.Thread.run(Thread.java:595)
Caused by: java.io.InterruptedIOException: operation interrupted
    at java.net.PlainDatagramSocketImpl.send(Native Method)
    at java.net.DatagramSocket.send(DatagramSocket.java:612)
    at org.jgroups.protocols.UDP._send(UDP.java:324)
    ... 16 more

This is happening during load testing on the server. Should I worry about it. Aside from getting that message in the log, everything seem to work OK.

Answer 1

Is it possible you are getting an error because you are sending a message to "null"?

ERROR - org.jgroups.protocols.UDP - failed sending message to null

Otherwise this is probably pretty hard for anyone else to help you out with without code samples, information on your network, the specific situation where your problem occurs, etc.

Answer 2

I wish it would be that simple. The way this is setup, you join a channel and any messages sent to that channel are replicated to all the node(s) that have joined. There's no destination specified in the code. The:

Caused by: java.io.InterruptedIOException: operation interrupted

Lead me to think there's a timeout happening or something.

Answer 3

In response to matt b, the "failed sending message to null" message is misleading. The true problem is the InterruptedIOException. This means that someone called interrupt() on the Thread that was sending UDP. Most likely, the interrupt is generated within JGroups. (Unless you started, and then stopped the JGroups channel.)

Looking at the stack trace, the interrupted I/O was from a Discovery protocol. It was trying to discover other cluster members. Thus, no message of yours was lost from this Exception.

We would have to know more to really figure this one out.

Answer 4

I get the same problem. 1)Created few Virtual IPs 2)Started multiple instances , with an interval of 20sec. 3)Which ever instance started first prints this exception

Out of the multi cast address , What I can see is that, Only first node is bound to 228.6.6.6

Any Idea ? Thanks