Check if a server is offline

How would I check if a server is offline. I tried using sockets, but it kicks everyone if the server is offline because of lag. How would I go about doing this with Bukkit?

I made a thread exactly like this, but for some reason it got locked before I could respond. Someone said something about netIO inside separate thread (async task). Can someone give me an example.
Another person said something about sockets. I tried that. By the time it times out the players time out.
Another guy said Use separate thread and ping the server. How would I do that.

 

I think that pinging the server is definitely the best way to do it.
Luckily minecraft server has it's own ping feature(How client's ping servers).
Take a look at the documentation here: http://wiki.vg/Server_List_Ping.
They way to ping should be self explanatory if you are familiar with sockets(And you might want to do it on a seperate thread).
(Please look at java examples!).

 

tommycake50 Okay that makes somewhat sense. How would I put this into a plugin? Can you give an example?

 

The page gives you a java example, if you were to copy and adapt that a bit then you would be able to create a class with all the methods you need to perform a ping .

 

tommycake50 Okay. I did not see the example.

EDIT: I meant to say I did not see it at first, but I found it.