My code for main class

package com.emc2vsa22.gmail;

import java.util.logging.Logger;

import org.bukkit.ChatColor;
import org.bukkit.command.Command;
import org.bukkit.command.CommandSender;
import org.bukkit.entity.Player;
import org.bukkit.plugin.PluginDescriptionFile;
import org.bukkit.plugin.PluginManager;
import org.bukkit.plugin.java.JavaPlugin;
import org.bukkit.potion.PotionEffect;
import org.bukkit.potion.PotionEffectType;

public class GoldCommandsPlugin extends JavaPlugin{
	public static GoldCommandsPlugin plugin;
	public final Logger logger = Logger.getLogger("Minecraft");

	@Override
	public void onDisable(){
		PluginDescriptionFile pdfFile = this.getDescription();
		this.logger.info(pdfFile.getName() + " ,the official CyberCraft Plugin, has been disabled.");
		getServer().getPluginManager().removePermission(new Permisssions().canPerformCommand);
	}

	@Override
	public void onEnable(){
		PluginDescriptionFile pdfFile = this.getDescription();
		PluginManager pm = this.getServer().getPluginManager();
		this.logger.info(pdfFile.getName() +  " ,the official CyberCraft Plugin, has been enabled." + " Version " + pdfFile.getVersion());

		pm.addPermission(new Permisssions().canPerformCommand);

	}

	public boolean onCommand(CommandSender sender, Command cmd, String commandLabel, String[] args){
		Player player = (Player) sender;
		if(commandLabel.equalsIgnoreCase("goldcommands") || commandLabel.equalsIgnoreCase("gc")){
			player.sendMessage(ChatColor.WHITE + "----- " + ChatColor.GOLD + "GoldCommands Help " + ChatColor.WHITE + "-----");
			player.sendMessage( ChatColor.GREEN + "/gc location" + ChatColor.GOLD + " Gives you you're location");
			player.sendMessage( ChatColor.GREEN + "/gc bed" + ChatColor.GOLD + " Gives you you're  bed location");
			player.sendMessage( ChatColor.GREEN + "/gc speed " + ChatColor.GOLD + "Allows you to set walking speed (requires permissions)");
			player.sendMessage( ChatColor.GREEN + "/gc time " + ChatColor.DARK_AQUA + "[morning:afternoon:night] " + ChatColor.GOLD + "Sets the time (requires permissions!)");
			player.sendMessage( ChatColor.GREEN + "/gc fly " + ChatColor.DARK_AQUA + "[on:off] " + ChatColor.GOLD + "Toggles flight (requires permissions!");
			player.sendMessage( ChatColor.GREEN + "/gc vanish " + ChatColor.GOLD + "Toggles invisibility (requires permissions");
			player.sendMessage( ChatColor.GREEN + "/gc juggernuat " + ChatColor.GOLD + "Toggles super-stregnth (requires permissions");
			player.sendMessage( ChatColor.GREEN + "/gc powder " + ChatColor.GOLD + "Go home, you're drunk!");
		}if(args.length == 1){
			if(args[0].equalsIgnoreCase("location")){
				player.sendMessage(ChatColor.GOLD + "You are located at " + ChatColor.GREEN + player.getLocation());
			}
			if(sender.hasPermission(new Permisssions().canPerformCommand)){
				if(args[0].equalsIgnoreCase("vanish")){
					player.addPotionEffect(new PotionEffect(PotionEffectType.INVISIBILITY, 1200, 1));
					player.sendMessage(ChatColor.GOLD + "You are invisible for 10 minutes!");
				}else{
					player.sendMessage(ChatColor.DARK_RED + "Unknown Command (Press /gc for help)");
				}
			}else{
				player.sendMessage(ChatColor.DARK_RED + "You don't have the required permission");
			}
		}
		return false;
	}
}