NullPointException, Why?

My only question is why I get a NullPointException on the line getConfig().set and getConfig().getDouble, and how I can fix it.

SetSpawn:

Code:java

 
public class SetSpawnCommand implements CommandExecutor{
 
    Main plugin;
 
    public boolean onCommand(CommandSender sender, Command cmd, String label, String[] args){
        if(!(sender instanceof Player)){
            sender.sendMessage(plugin.playeronly);
            return true;
        }
 
        Player player = (Player) sender;
 
        if(cmd.getName().equalsIgnoreCase("setspawn")){
            if(!player.hasPermission("spawn.set")){
                player.sendMessage(plugin.nopermission);
                return true;
            }
            if(args.length == 0){
 
                plugin.getConfig().set("Spawn.X", player.getLocation().getBlockX());
                plugin.getConfig().set("Spawn.Y", player.getLocation().getBlockY());
                plugin.getConfig().set("Spawn.Z", player.getLocation().getBlockZ());
                plugin.getConfig().set("Spawn.World", player.getLocation().getWorld().getName());
                plugin.saveConfig();
 
                player.sendMessage(ChatColor.GRAY + "The Spawn has been set on your location!");
                return true;
            }
            if(args.length >= 1){
                player.sendMessage(ChatColor.RED + "Too many arguments, please use /setspawn.");
                return true;
            }
        }
        return true;
    }
}
 
 

Spawn:

Code:java

 
public class SpawnCommand implements CommandExecutor{
 
    Main plugin;
 
    public boolean onCommand(CommandSender sender, Command cmd, String label, String[] args){
        if(!(sender instanceof Player)){
            sender.sendMessage(plugin.playeronly);
            return true;
        }
 
        Player player = (Player) sender;
 
        if(cmd.getName().equalsIgnoreCase("spawn")){
            if(plugin.getConfig().getConfigurationSection("Spawn") == null){
                player.sendMessage(ChatColor.GRAY + "There is no spawn set!");
                return true;
            }
 
            World w = Bukkit.getServer().getWorld(plugin.getConfig().getString("Spawn.World"));
            double x = plugin.getConfig().getDouble("Spawn.X");
            double y = plugin.getConfig().getDouble("Spawn.Y");
            double z = plugin.getConfig().getDouble("Spawn.Z");
 
            player.teleport(new Location(w, x, y, z));
 
            player.sendMessage(ChatColor.GRAY + "You have been teleported to spawn.");
            return true;
        }
        return true;
    }
}
 
 

 

@Doubtstand The field 'plugin' hasn't been initialized, so it and any getter methods will return null.

 

How can I intialize it?

 

@Doubtstand
You set it to something?

Did you learn Java? This is something very basic.

 

I intialized it, but when I do /spawn, It teleports me on the corner of 4 blocks, I want the player to spawn on the block itself, how?

 

@Doubtstand
Add or subtract 0.5 from the x and z.

 

The methods won't return anything. The methods won't even be called because it's on a null Object.

 

Initialize plugin: Plugin plugin = Bukkit.getServer().getPluginManager().getPlugin("plugin name");

also if you want the location to be exact do: double x = p.getLocation().getX()

To teleport to the middle of a block do:
double x = p.getLocation().getBlockX() + 0.5;
double y = p.getLocation().getBlockY();
double z = p.getLocation().getBlockZ() + 0.5;