InstantKill

package me.moe097.InstantKill;

import org.bukkit.ChatColor;
import org.bukkit.command.Command;
import org.bukkit.command.CommandSender;
import org.bukkit.entity.EntityType;
import org.bukkit.entity.Player;
import org.bukkit.entity.Projectile;
import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.entity.EntityDamageByEntityEvent;
import org.bukkit.plugin.java.JavaPlugin;

public class MainClass extends JavaPlugin implements Listener {

    @Override
    public void onEnable() {
        getLogger().info("InstantKill has been enabled!");
        getServer().getPluginManager().registerEvents(this, this);
    }

    @Override
    public void onDisable() {
        getLogger().info("InstantKill has been disabled!");
    }

    private boolean instantkill = false;

    @EventHandler
    public void onShotEvent(EntityDamageByEntityEvent event)
  {
        if(instantkill) {
            if(event.getDamager() instanceof Projectile)
            {

                Projectile p = (Projectile) event.getDamager();
                if(p.getType() == EntityType.ARROW)
                {
                     Player player = (Player) event.getEntity();
                     player.setHealth(0);
                   }
                }
            }
    }

    @Override
    public boolean onCommand(CommandSender sender, Command cmd, String commandLabel, String[] args) {
        if(sender instanceof Player) {
            Player player = (Player) sender;
              if(commandLabel.equalsIgnoreCase("InstantKillOn") && player.hasPermission("instantkill.on")) {
                  instantkill = true;
                  player.sendMessage(ChatColor.RED + "Instant Kill has been turned on! Players will die with one shot from a bow!");
              }
              if(commandLabel.equalsIgnoreCase("InstantKillOff") && player.hasPermission("instantkill.off")) {
                  instantkill = false;
                  player.sendMessage(ChatColor.RED + "Instant Kill has been turned off! Players will die with normal amount of damage!");
            }
      }
        return false;
   }
}