TP.down doesn't catch/handle the InterruptedIOException that can be thrown from the underlying send call when interrupted:

try

{ if(use_outgoing_packet_handler) outgoing_queue.put(msg); else send(msg, dest, multicast); }

catch(QueueClosedException closed_ex) {
}
catch(InterruptedException interruptedEx) {
}
catch(Throwable e) {
if(log.isErrorEnabled())

{ String dst=msg.getDest() == null? "null" : msg.getDest().toString(); log.error("failed sending message to " + dst + " (" + msg.getLength() + " bytes)", e.getCause()); }

}

This can lead to it being logged repeatedly at the ERROR level:

2007-11-14 10:02:30,040 ERROR -> (PingSender) [UDP] failed sending message to null (0 bytes)
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:316)
at org.jgroups.protocols.UDP.sendToAllMembers(UDP.java:286)
at org.jgroups.protocols.TP.doSend(TP.java:937)
at org.jgroups.protocols.TP.send(TP.java:926)
at org.jgroups.protocols.TP.down(TP.java:712)
at org.jgroups.stack.Protocol.receiveDownEvent(Protocol.java:499)
at org.jgroups.stack.Protocol.passDown(Protocol.java:533)
at org.jgroups.protocols.PING.sendMcastDiscoveryRequest(PING.java:214)
at org.jgroups.protocols.PING.sendGetMembersRequest(PING.java:208)
at org.jgroups.protocols.PingSender.run(PingSender.java:59)
at java.lang.Thread.run(Thread.java:595)

2.5/2.6 don't handle the InterruptedIOException either, but since this was reported with EAP 4.2 (JGroups 2.4.1.SP3), I 'd like to see it in 2.4.2 if possible. That way, it can make it into a 4.2/4.3 EAP CP.