@EventHandler
public void onJoin ( PlayerJoinEvent event )
{
    sendActionBar ( event.getPlayer ( ), ChatColor.RED + "hai" );
}

public Class< ? > getNMSClass ( String classname )
{
    String version = getServer ( ).getClass ( ).getPackage ( ).getName ( ).replace ( ".", "," ).split ( "," )[ 3 ] + ".";
    String name = "net.minecraft.server." + version + classname;
    Class< ? > nmsClass = null;
    try
    {
        nmsClass = Class.forName ( name );
    } catch ( ClassNotFoundException e )
    {
        e.printStackTrace ( );
    }
    return nmsClass;
}

// Skionz @ Bukkit.org
public Object getConnection ( Player player ) throws SecurityException, NoSuchMethodException, NoSuchFieldException, IllegalArgumentException, IllegalAccessException, InvocationTargetException, InvocationTargetException
{
    Method getHandle = player.getClass ( ).getMethod ( "getHandle" );
    Object nmsPlayer = getHandle.invoke ( player );
    Field conField = nmsPlayer.getClass ( ).getField ( "playerConnection" );
    Object con = conField.get ( nmsPlayer );
    return con;
}

public void sendActionBar ( Player player, String message )
{
    try
    {
        Class< ? > packetPlayOutChat = getNMSClass ( "PacketPlayOutChat" );
        Constructor< ? > packetConstructor = packetPlayOutChat.getConstructor ( getNMSClass ( "IChatBaseComponent" ), byte.class );
        Class< ? > ichat = getNMSClass ( "IChatBaseComponent" );
        Class< ? > chatSerializer = ichat.getClasses ( )[ 0 ];
        Method csA = chatSerializer.getMethod ( "a", String.class );
        Object component = csA.invoke ( chatSerializer, "{\"text\": \"" + message + "\"}" );
        Object packet = packetConstructor.newInstance ( component, ( byte ) 2 );
        Method sendPacket = getConnection ( player ).getClass().getMethod ( "sendPacket", (getNMSClass ( "Packet" )) packetPlayOutChat.getSuperclass () );
        sendPacket.invoke ( packet );
    } catch ( Exception e )
    {
        e.printStackTrace ( );
    }
}