java - what does here_now(String args0) in Pubnub do? -

I am trying to subscribe to a particulair channel to customers. I found an example on GIT which used the function with 2 parameters here, like this:

  pubnub.hereNow (channel, new callback) {public zero success callback (string Channel, Object Message) {notifyUser ("Here:" + Message);} Public Zero ErrorColorback (String Channel, Object Message) {notifyUser ("Here:" + Message);}});   
 But here_now () function in my company's application takes only one parameter i.e a string. Am I new to the relatively new pubnub Can someone tell me what is this parameter? Is this the name of a channel? How do I specify call back work? I can not find any document related to string agre  
 thanks   
 
 < P> Please run PubNubDemoConsole.java ... you can walk on how all API calls work.  
 Specifically, here_now ():  
  
 (Looks like a lot above)  
 You really do The arguments are passing. The first is the channel name that you want statistics, the second parameter is the callback function to give success or error results.  
 Ensure that you are also on the latest PubNub for the Java version: