Weird NPE on pub socket

[MichaelScofield]

This was my pseudo code in the beginning (in an singleton service object):
pub = ctx.createSocket(ZMQ.PUB);
pub.bind("tcp://*.5556");
While(!stop) {
MyObject o = aConcurrentQueue.poll()
if (o != null) {
pub.sendMore(e.getTopic());
pub.send(e.getBody());
} else {
Thread.sleep(10);
}
}
However, it produced NPE like:
java.lang.NullPointerException
at zmq.Mtrie.match(Mtrie.java:353)
at zmq.XPub.xsend(XPub.java:179)
at zmq.SocketBase.send(SocketBase.java:598)
at org.zeromq.ZMQ$Socket.send(ZMQ.java:1002)
at org.zeromq.ZMQ$Socket.send(ZMQ.java:988)
(btw, I'm using jeromq 0.3.0)
Can't really figure out why this happened, any help would be thankful!

[miniway]

Could you please post your SUB part of the failed case?

[MichaelScofield]

@miniway
thx for the comment, but the SUB part code is that I can't access, nor control. All I know about it is just simple straightforward connect, subscribe and unsubscribe :(
I read the source code of Mtrie.java, and line 353 is: if (current.pipes != null)
Sorry I really don't get it under what circumstance will the var "current" be NULL...

[miniway]

Please try with a modified jar, https://www.dropbox.com/s/7xvbttps35a0j5b/jeromq-0.3.0-SNAPSHOT.jar

It contains a fix at the Mtrie.java. If it fixes your problem, I'm going to publish the fix to public.

[MichaelScofield]

ok, I'll try this new jar, thx~

[MichaelScofield]

still remains the problem... :(

[miniway]

:(
So, what kinds of topics? If I know the exact list of topics it would be helpful, because the Mtrie builds trees one character by one. And how many client usually connect?

[miniway]

Please try it once more with https://www.dropbox.com/s/7xvbttps35a0j5b/jeromq-0.3.0-SNAPSHOT.jar

The url is the same before but the file has an another fix.

[MichaelScofield]

The topics are like "ping", "chat" etc., just a fixed set of Strings. I'll test on the new jar, hope it'll work :)

[MichaelScofield]

have run the new jar for a day without the NPE, thought it ok, thx~

[MichaelScofield]

it would be nicer if u merge the change to the master, so I don't need to maintain the jar myself instead of maven~

[miniway]

I've also updated the jeromq-0.3.0-SNAPSHOT at sonatype. Your maven will download the latest jar