How to send messages from server to client?

Question

I am going to implement something similar to Facebook notification and this website (StackOverflow\'s notification which is notifying us if anyone write a comment/answer etc for

Answer 1

mqtt can be used for server pushing and message broadcasting.

There are more detail information in http://mqtt.org/.

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Updated: Jul 11, 2013

Mqtt is a publish/subscribe, extremely simple and lightweight messaging protocol. If server is a publisher and client browser subscribe the topic which server publish to, then server can push message to client directly.

Some useful resource:

Mosquitto is an open sourced mqtt server. Easy to install and configure.

mqtt-client is a proven powerful java mqtt client.