========/ checker.java /========
public class checker {
    private static double player_position_x;
    private static double player_position_z;

    @EventHandler
    public static void coordchecker() {
        for(Player player : Bukkit.getOnlinePlayers()) {
            player_position_x = player.getLocation().getX();
            player_position_x = player.getLocation().getZ();

            if (player_position_x >= 1000 || player_position_z >= 1000) {
                player.sendMessage("X=1000 / Z=1000");
            }
        }
    }
}
=======/ main.java /=======
checker.coordchecker();