I dont know why my plugin wont work

package me.vanish.main; //change this

import java.util.ArrayList;
import java.util.List;

import org.bukkit.Bukkit;
import org.bukkit.command.Command;
import org.bukkit.command.CommandSender;
import org.bukkit.entity.Player;
import org.bukkit.plugin.java.JavaPlugin;

public class vanish extends JavaPlugin //MAKE SURE TO ADD ALL IMPORTS
{
	@Override
	public void onEnable()
	{
		System.out.println("Vanish Plugin Has Been Enabled");
	}

	List<Player> vanished = new ArrayList<>();

	public void onDisable()
	{
		System.out.println("Vanish Plugin Has Been Disabled");
	}

	public boolean onCommand(CommandSender sender, Command cmd, String label, String[] args)
	{
		if (sender instanceof Player)
		{
			Player player = (Player) sender;

			if(cmd.getName().equalsIgnoreCase("vanish"))
			{
				if(vanished.contains(player))
				{
					vanished.remove(player);
					for(Player target : Bukkit.getOnlinePlayers())
					{
						target.showPlayer(player);
					}

					player.sendMessage("You are unvanished!");
				} else
				{
					vanished.add(player);
					for(Player target : Bukkit.getOnlinePlayers())
					{
						target.hidePlayer(player);
					}

					player.sendMessage("You are vanished");
				}
			}
		}
		return true;
	}
}