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

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.