Chang guis title using protocollib

Hi guys! I'm trying to change the GUI title with protocollib.
But I have no idea how to read the gui names.

I tried

Code:

ProtocolLibrary.getProtocolManager().addPacketListener(new PacketListener() {
            public Plugin getPlugin() {
                return Bukkit.getPluginManager().getPlugin("ProtocolLibTest");
            }

            public ListeningWhitelist getReceivingWhitelist() {
                return ListeningWhitelist.newBuilder().gamePhase(GamePhase.PLAYING).highest().types(PacketType.Play.Server.OPEN_WINDOW).build();
            }

            public ListeningWhitelist getSendingWhitelist() {
                return ListeningWhitelist.newBuilder().gamePhase(GamePhase.PLAYING).highest().types(PacketType.Play.Server.OPEN_WINDOW).build();
            }

            public void onPacketReceiving(PacketEvent e) {
                return;
            }

            @Override
            public void onPacketSending(PacketEvent e) {
                if (!(e.getPacket().getType() == PacketType.Play.Server.OPEN_WINDOW))
                    return;
                PacketContainer wrapper = e.getPacket();
                System.out.println(wrapper.getStrings().read(1));
   
                // wrapper.getStrings().writeSafely(3, invTitle);
                // e.setPacket(wrapper);
                // setMenuTitle = false;
            }

        });

But it only return minecraft:chest
When I read 1, it show up this:


I want to read and set the "c", can any one help me out?

 

@1461748123
Use reflection to get the field and change it. Here is an example:
I will use this class

Code:

public class Stuff {
    private String stuff = "hello";
}

Here is how you would get the field 'stuff' and change the value

Code:

public static void main(String[] args) {
    Stuff object = new Stuff();
    Field field = Stuff.class.getDeclaredField("stuff"); //Gets the field
    field.setAccessible(true); //Lets us modify it
    field.set(object, "The New Value"); //Changes the value of 'stuff' in the object we created above
}

 

@Skionz

Can you help me out?
I have no idea how to do it.
I tried this and it gives me error:

Code:

Field field = e.getPacket().getClass().getDeclaredField("c");
                    field.setAccessible(true);
                    System.out.println(field.getType());