//first class
package com.courbie.helloworld;

import org.bukkit.event.EventHandler;
import org.bukkit.plugin.PluginManager;
import org.bukkit.plugin.java.JavaPlugin;

public class Main extends JavaPlugin{

    @EventHandler
    public void onEnable() {

        getLogger().info("Hey Courbie, have a good day!");
        PluginManager pm = getServer().getPluginManager();
        MyFirstListener listener = new MyFirstListener();
        pm.registerEvents(listener, this);
    }

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

}

//Second class
package com.courbie.helloworld;

import org.bukkit.event.EventHandler;
import org.bukkit.event.Listener;
import org.bukkit.event.player.PlayerJoinEvent;

public class MyFirstListener implements Listener{

    //Constructor
    public void FirstListener (final Main Plugin) {

    }

    //EventHandler
    @EventHandler
    public void onPlayerJoin(PlayerJoinEvent event) {

        event.getPlayer().sendMessage("Hello! How are you today Courbie?");

    }

}