java.lang.Runtimeexception: Unable to start Activity Componentinfo{}: java.lang.Nullpointerexception by checking my input

Question

I’m new to android development and am passing a swing chat for android. The idea is to use a server socket that makes the connection. This is the third attempt to make it work... I received the following errors:

E/AndroidRuntime: FATAL EXCEPTION: main
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.stevenilson.appchat/com.stevenilson.appchat.TelaChat}: java.lang.NullPointerException
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2114)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2139)
    at android.app.ActivityThread.access$700(ActivityThread.java:143)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1241)
    at android.os.Handler.dispatchMessage(Handler.java:99)
    at android.os.Looper.loop(Looper.java:137)
    at android.app.ActivityThread.main(ActivityThread.java:4960)
    at java.lang.reflect.Method.invokeNative(Native Method)
    at java.lang.reflect.Method.invoke(Method.java:511)
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1038)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:805)
    at dalvik.system.NativeStart.main(Native Method)
 Caused by: java.lang.NullPointerException
    at com.stevenilson.appchat.TelaChat.conectar(TelaChat.java:84)
    at com.stevenilson.appchat.TelaChat.onCreate(TelaChat.java:40)
    at android.app.Activity.performCreate(Activity.java:5203)
    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1094)
    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2078)
    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2139) 
    at android.app.ActivityThread.access$700(ActivityThread.java:143) 
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1241) 
    at android.os.Handler.dispatchMessage(Handler.java:99) 
    at android.os.Looper.loop(Looper.java:137) 
    at android.app.ActivityThread.main(ActivityThread.java:4960) 
    at java.lang.reflect.Method.invokeNative(Native Method) 
    at java.lang.reflect.Method.invoke(Method.java:511) 
    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1038) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:805) 
    at dalvik.system.NativeStart.main(Native Method)

follows the main code:

package com.stevenilson.appchat;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.Toast;

import java.io.IOException;
import java.io.ObjectInputStream;
import java.io.ObjectOutputStream;
import java.net.Socket;
import java.util.logging.Level;
import java.util.logging.Logger;

public class TelaChat extends AppCompatActivity {

    EditText textMessage;
    ListView mensagens;
    ArrayAdapter<String> adapter;
    ChatMessage message;
    Socket socket;
    ClienteService service;
    ObjectOutputStream outputStream;
    ObjectInputStream input;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_tela_chat);

        textMessage = findViewById(R.id.textBox);
        mensagens = findViewById(R.id.messagesView);

        adapter = new ArrayAdapter<>(this, android.R.layout.simple_list_item_1);
        mensagens.setAdapter(adapter);

        conectar();//linha 40 que recebe erro
    }
    @Override
    protected void onDestroy() {
        super.onDestroy();

        Toast.makeText(TelaChat.this, "Você saiu do Chat!", Toast.LENGTH_SHORT).show();
    }

    private class Run implements Runnable {
        public void run() {
            try {
                while ((message = (ChatMessage) input.readObject()) != null)  {
                    ChatMessage.Action action = message.getAction();
                    if (action.equals(ChatMessage.Action.CONNECT)) {
                        connected(message);
                    } else if (action.equals(ChatMessage.Action.DISCONNECT)) {
                        socket.close();
                        onDestroy();
                    } else if(action.equals(ChatMessage.Action.SEND_ONE)) {
                        receive(message);
                    }
                }
            } catch (IOException ex) {
                Logger.getLogger(TelaChat.class.getName()).log(Level.SEVERE, null, ex);
            } catch (ClassNotFoundException ex) {
                Logger.getLogger(TelaChat.class.getName()).log(Level.SEVERE, null, ex);
            }
        }
    }

    public void enviarMensagem(View view) {
        sendMessage();
    }

    private void sendMessage(){
        adapter.add(textMessage.getText().toString());
        this.message.setAction(ChatMessage.Action.SEND_ALL);

    }

    public void conectar() {

        try {
            this.input = new ObjectInputStream(socket.getInputStream()); // linha 84 que recebe erro;
        } catch (IOException ex) {
            Logger.getLogger(TelaChat.class.getName()).log(Level.SEVERE, null, ex);
        }

        new Thread(new Run()).start();

        this.message.setAction(ChatMessage.Action.CONNECT);
        this.socket = this.service.connect();
        Toast.makeText(TelaChat.this, "Você está conectado!", Toast.LENGTH_SHORT).show();
    }
    private void connected(ChatMessage message) {
        if (message.getText().equals("NO")) {
            Toast.makeText(TelaChat.this, "Coneão não realizada!\nTente novamente com um novo nome.", Toast.LENGTH_SHORT).show();
            message.setAction(ChatMessage.Action.DISCONNECT);
            this.service.send(message);
            onDestroy();
            return;
        }
        Toast.makeText(TelaChat.this, "Você está conectado no chat!", Toast.LENGTH_SHORT).show();
    }

    private void receive(ChatMessage message) {
        adapter.add(message.getText());
    }


}

xml code:

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:clipToPadding="false"
    android:focusableInTouchMode="true"
    tools:context=".MainActivity">

    <ListView
        android:id="@+id/messagesView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_weight="2"
        android:divider="#fff" />

    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="#fff"
        android:orientation="horizontal">

        <EditText
            android:id="@+id/textBox"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:layout_weight="2"
            android:ems="10"
            android:hint="Escrever..."
            android:inputType="text"
            android:paddingHorizontal="10dp"
            android:text="" />

        <ImageButton
            android:id="@+id/buttonSend"
            android:onClick="enviarMensagem"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_gravity="center"
            android:layout_marginHorizontal="10dp"
            android:padding="20dp"
            android:scaleType="fitCenter"
            android:src="@android:drawable/ic_menu_send" />

    </LinearLayout>
</RelativeLayout>

if you need more information about the other classes just ask.

Obs: project of fair for day 20 November;