Convert 1.8.9 to 1.16.5 one line

[frontlisterd]

So I was told that "only one string" needed to change for this 1.8.9 mod to become a 1.16.5 mod. Im not very sure what this line is as I am new to this coding thing, so I thought I might ask around. Thanks in advance.

Here is pt.1 of the code:
 

package studio.dreamys.gui;

import com.google.gson.JsonObject;
import com.google.gson.JsonParser;
import java.awt.Color;
import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.URL;
import net.minecraft.client.gui.GuiButton;
import net.minecraft.client.gui.GuiScreen;
import net.minecraft.client.gui.GuiTextField;
import net.minecraft.client.gui.ScaledResolution;
import net.minecraft.util.Session;
import org.apache.commons.io.IOUtils;
import org.lwjgl.input.Keyboard;
import studio.dreamys.TokenAuth;

public class SessionGui extends GuiScreen {
    private GuiScreen previousScreen;
    private String status = "Session:";
    private GuiTextField sessionField;
    private ScaledResolution sr;

    public SessionGui(GuiScreen previousScreen) {
        this.previousScreen = previousScreen;
    }

    public void func_73866_w_() {
        Keyboard.enableRepeatEvents(true);
        this.sr = new ScaledResolution(this.field_146297_k);
        this.sessionField = new GuiTextField(1, this.field_146297_k.field_71466_p, this.sr.func_78326_a() / 2 - 100, this.sr.func_78328_b() / 2, 200, 20);
        this.sessionField.func_146203_f(32767);
        this.sessionField.func_146195_b(true);
        this.field_146292_n.add(new GuiButton(998, this.sr.func_78326_a() / 2 - 100, this.sr.func_78328_b() / 2 + 30, 200, 20, "Login"));
        this.field_146292_n.add(new GuiButton(999, this.sr.func_78326_a() / 2 - 100, this.sr.func_78328_b() / 2 + 60, 200, 20, "Restore"));
        super.func_73866_w_();
    }

    public void func_146281_b() {
        Keyboard.enableRepeatEvents(false);
        super.func_146281_b();
    }

    public void func_73863_a(int mouseX, int mouseY, float partialTicks) {
        this.func_146276_q_();
        this.field_146297_k.field_71466_p.func_78276_b(this.status, this.sr.func_78326_a() / 2 - this.field_146297_k.field_71466_p.func_78256_a(this.status) / 2, this.sr.func_78328_b() / 2 - 30, Color.WHITE.getRGB());
        this.sessionField.func_146194_f();
        super.func_73863_a(mouseX, mouseY, partialTicks);
    }

    protected void func_146284_a(GuiButton button) throws IOException {
        if (button.field_146127_k == 998) {
            try {
                String session = this.sessionField.func_146179_b();
                String username;
                String uuid;
                String token;
                if (session.contains(":")) {
                    username = session.split(":")[0];
                    uuid = session.split(":")[1];
                    token = session.split(":")[2];
                } else {
                    HttpURLConnection c = (HttpURLConnection)(new URL("https://api.minecraftservices.com/minecraft/profile/")).openConnection();
                    c.setRequestProperty("Content-type", "application/json");
                    c.setRequestProperty("Authorization", "Bearer " + this.sessionField.func_146179_b());
                    c.setDoOutput(true);
                    JsonObject json = (new JsonParser()).parse(IOUtils.toString(c.getInputStream())).getAsJsonObject();
                    username = json.get("name").getAsString();
                    uuid = json.get("id").getAsString();
                    token = session;
                }

                this.field_146297_k.field_71449_j = new Session(username, uuid, token, "mojang");
                this.field_146297_k.func_147108_a(this.previousScreen);
            } catch (Exception var9) {
                this.status = "§cError: Couldn't set session (check mc logs)";
                var9.printStackTrace();
            }
        }

        if (button.field_146127_k == 999) {
            try {
                this.field_146297_k.field_71449_j = TokenAuth.originalSession;
                this.field_146297_k.func_147108_a(this.previousScreen);
            } catch (Exception var8) {
                this.status = "§cError: Couldn't restore session (check mc logs)";
                var8.printStackTrace();
            }
        }

        super.func_146284_a(button);
    }

    protected void func_73869_a(char typedChar, int keyCode) throws IOException {
        this.sessionField.func_146201_a(typedChar, keyCode);
        if (1 == keyCode) {
            this.field_146297_k.func_147108_a(this.previousScreen);
        } else {
            super.func_73869_a(typedChar, keyCode);
        }

    }
}

and heres pt.2 :
 

package studio.dreamys;

import java.awt.Color;
import net.minecraft.client.Minecraft;
import net.minecraft.client.gui.GuiButton;
import net.minecraft.client.gui.GuiMultiplayer;
import net.minecraft.util.Session;
import net.minecraftforge.client.event.GuiScreenEvent;
import net.minecraftforge.common.MinecraftForge;
import net.minecraftforge.fml.common.Mod;
import net.minecraftforge.fml.common.Mod.EventHandler;
import net.minecraftforge.fml.common.event.FMLPreInitializationEvent;
import net.minecraftforge.fml.common.eventhandler.SubscribeEvent;
import studio.dreamys.gui.SessionGui;

@Mod(
    modid = "ta",
    name = "TokenAuth",
    version = "1.1.0"
)
public class TokenAuth {
    public static Minecraft mc = Minecraft.func_71410_x();
    public static Session originalSession;

    public TokenAuth() {
    }

    @EventHandler
    public void preInit(FMLPreInitializationEvent e) {
        MinecraftForge.EVENT_BUS.register(this);
    }

    @SubscribeEvent
    public void onInitGuiPost(GuiScreenEvent.InitGuiEvent.Post e) {
        if (e.gui instanceof GuiMultiplayer) {
            e.buttonList.add(new GuiButton(999, 5, 5, 100, 20, "TokenAuth"));
        }

    }

    @SubscribeEvent
    public void onDrawScreenPost(GuiScreenEvent.DrawScreenEvent.Post e) {
        if (e.gui instanceof GuiMultiplayer) {
            String status = String.format("User: §a%s §rUUID: §a%s", mc.field_71449_j.func_111285_a(), mc.field_71449_j.func_148255_b());
            Minecraft.func_71410_x().field_71466_p.func_78276_b(status, 115, 10, Color.WHITE.getRGB());
        }

    }

    @SubscribeEvent
    public void onActionPerformedPre(GuiScreenEvent.ActionPerformedEvent.Pre e) {
        if (e.gui instanceof GuiMultiplayer && e.button.field_146127_k == 999) {
            Minecraft.func_71410_x().func_147108_a(new SessionGui(e.gui));
        }

    }

    static {
        originalSession = mc.field_71449_j;
    }
}

 

[maksvavrik86]

I would be glad if someone helps with this question or at least show a similar mod