[zamalek]

It's possible by blocking the thread that's reading the XML, but now you're in thread-per-client territory, and that doesn't scale.

[Flowdalic]

Smack uses an XML pull parser and non-blocking I/O. It does so by splitting the XMPP stream top-level elements first and only feeding complete elements to the pull parser.

[forty]

https://github.com/igniterealtime/Smack/blob/master/smack-xm...

I don't see any opportunity not to block when calling "next"