tab.java

        @SuppressWarnings("unused")
	public static void tab(Player player, String header, String footer){
		CraftPlayer cp = (CraftPlayer) player;
		PlayerConnection connection = cp.getHandle().playerConnection;
		IChatBaseComponent header1 = ChatSerializer.a("{\"text\": \""+header+"\"}");
		IChatBaseComponent footer1 = ChatSerializer.a("{\"text\": \""+footer+"\"}");
		PacketPlayOutPlayerListHeaderFooter packet = new PacketPlayOutPlayerListHeaderFooter();

		try{
			Field headerField = packet.getClass().getDeclaredField("a");
	        headerField.setAccessible(true);
	        headerField.set(packet, header1);
	        headerField.setAccessible(!headerField.isAccessible());

	        Field footerField = packet.getClass().getDeclaredField("b");
	        footerField.setAccessible(true);
	        footerField.set(packet, footer1);
	        footerField.setAccessible(!footerField.isAccessible());

	        cp.getHandle().playerConnection.sendPacket(packet);

		} catch (Exception e){
			e.printStackTrace();
			System.out.println(e.getMessage());
		}
	}