Run some code after X amount of time

How can I make it so after a certain amount of time the code is run. So for example when a player logs in it waits 10 seconds and then sends a message.

What I want to do is something like this:

Code:java

 
if(worldOne.getPlayers().size() <= 0) { //if a world has less than 0 people or 0 people in it
     //wait 10 seconds
          player.sendMessage("test"); //send the message "test"
}
 

Thanks in advance!

 

If its time based then use the scheduler http://wiki.bukkit.org/Scheduler_Programming

If its command or action based like "did something x times" then you would have to implement your own logic when this happens and execute your code or run the scheduler.

For your example you would need to listen in PlayerQuitEvent and simply check if the PlayerOnline count is below your limit. ( < 1 cause i believe that the player that is quitting still counts as player but you might have to check that ).

You can run your code then in a scheduler or simply leave it in the event .. its up to you.

 

Code:java

 
if(worldOne.getPlayers().size() <= 0) {
Bukkit.getScheduler().scheduleSyncDelayedTask(plugin, new Runnable() {
public void run() {
player.sendMessage("test"); //send the message "test"
}
}, 200L);
}

 

What does 200L mean? Is it 200 ticks?

 

ThunderWaffeMC
Yes

Edit: If you wanted it in seconds just replace it with 20 * (amount of seconds)