Envoi de données vers un serveur avec un thread différent

Bonjour,
Je débute avec Android (Java) et je dois faire une application qui envoie des données sur un serveur.
Pour les tests, je fais mon propre serveur local sur lequel je connecte mon application sur un thread différent (ce qui semble obligatoire avec Android).
Je n'arrive pas à comprendre comment ça fonctionne!
J'ai fais un petit démo très simple : une classe «MainActivity» (vide), une classe «Connecteur» et une classe «Serveur».
Le problème semble venir du fait que le «PrintWriter» qui est créé dans «Connecteur» est null lorsque vient le temps d'envoyer des messages au serveur... et je ne comprend pas pourquoi.

Voici la simple classe «MainActivity»

Code:

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import androidx.appcompat.app.AppCompatActivity;
 
import android.os.Bundle;
import android.util.Log;
 
public class MainActivity extends AppCompatActivity {
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
 
        Connecteur connecteur = new Connecteur();
        connecteur.sendMessage("toto");
 
    }
 
}

Voici la classe «Connecteur»

Code:

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import java.io.PrintWriter;
import java.net.Socket;
import java.net.UnknownHostException;
import java.util.concurrent.RejectedExecutionException;
 
 
public class Connecteur implements Runnable {
 
    private Socket clientSocket;
    private PrintWriter out;
 
   public Connecteur() {
       Thread newThread =new Thread(this);
       newThread.start();
   }
 
    public void sendMessage(String text) {
        out.println(text);
    }
 
    @Override
    public void run() {
        try {
            Serveur serveur = new Serveur();
            serveur.start(4444);
 
            clientSocket = new Socket("127.0.0.1", 4444);
            out = new PrintWriter(clientSocket.getOutputStream(), true);
 
        } catch (UnknownHostException e) {
            e.printStackTrace();
        } catch (IOException  e) {
            e.printStackTrace();
        } catch ( RejectedExecutionException e) {
            e.printStackTrace();
        }
    }
 
}

Voici la classe «Serveur»

Code:

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import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.ServerSocket;
import java.net.Socket;
 
public class Serveur {
 
    private ServerSocket serverSocket;
    private Socket clientSocket;
    private BufferedReader in;
 
    public void start(int port) {
        try {
            serverSocket = new ServerSocket(port);
            clientSocket = serverSocket.accept();
            in = new BufferedReader(new InputStreamReader(clientSocket.getInputStream()));
        } catch (IOException e) {
            e.printStackTrace();
        }
 
        String inputLine;
        while (true) {
            try {
                if (!((inputLine = in.readLine()) != null)) break;
                if ("stop".equals(inputLine)) {
                    break;
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }
 
}

Voici le log d'erreur (un peu long, je suis désolée!)

Code:

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2020-06-19 15:01:28.282 31102-31102/? E/Zygote: isWhitelistProcess - Process is Whitelisted
2020-06-19 15:01:28.283 31102-31102/? E/libpersona: scanKnoxPersonas
2020-06-19 15:01:28.283 31102-31102/? E/libpersona: Couldn't open the File - /data/system/users/0/personalist.xml - No such file or directory
2020-06-19 15:01:28.288 31102-31102/? W/SELinux: SELinux selinux_android_compute_policy_index : Policy Index[2],  Con:u:r:zygote:s0 RAM:SEPF_SM-J260A_8.1.0_0008, [-1 -1 -1 -1 0 1]
2020-06-19 15:01:28.290 31102-31102/? I/SELinux: SELinux: seapp_context_lookup: seinfo=untrusted, level=s0:c512,c768, pkgname=com.inf4018.myapplication 
2020-06-19 15:01:28.318 31102-31102/? I/zygote: Late-enabling -Xcheck:jni
2020-06-19 15:01:28.566 31102-31102/? D/TimaKeyStoreProvider: TimaKeyStore is not enabled: cannot add TimaSignature Service and generateKeyPair Service
2020-06-19 15:01:28.567 31102-31102/? D/ActivityThread: Added TimaKeyStore provider
2020-06-19 15:01:28.856 31102-31102/com.inf4018.myapplication D/MDO: MDO if sIsMdo=false, sIsCheckMdo=false, uid = 10169
2020-06-19 15:01:28.861 31102-31102/com.inf4018.myapplication D/Proxy: mdoP is null: 10169
2020-06-19 15:01:29.332 31102-31102/com.inf4018.myapplication I/zygote: Rejecting re-init on previously-failed class java.lang.Class<androidx.core.view.ViewCompat$2>: java.lang.NoClassDefFoundError: Failed resolution of: Landroid/view/View$OnUnhandledKeyEventListener;
2020-06-19 15:01:29.332 31102-31102/com.inf4018.myapplication I/zygote:     at void androidx.core.view.ViewCompat.setBackground(android.view.View, android.graphics.drawable.Drawable) (ViewCompat.java:2559)
2020-06-19 15:01:29.332 31102-31102/com.inf4018.myapplication I/zygote:     at void androidx.appcompat.widget.ActionBarContainer.<init>(android.content.Context, android.util.AttributeSet) (ActionBarContainer.java:63)
2020-06-19 15:01:29.332 31102-31102/com.inf4018.myapplication I/zygote:     at java.lang.Object java.lang.reflect.Constructor.newInstance0(java.lang.Object[]) (Constructor.java:-2)
2020-06-19 15:01:29.332 31102-31102/com.inf4018.myapplication I/zygote:     at java.lang.Object java.lang.reflect.Constructor.newInstance(java.lang.Object[]) (Constructor.java:334)
2020-06-19 15:01:29.332 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.View android.view.LayoutInflater.createView(java.lang.String, java.lang.String, android.util.AttributeSet) (LayoutInflater.java:647)
2020-06-19 15:01:29.332 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.View android.view.LayoutInflater.createViewFromTag(android.view.View, java.lang.String, android.content.Context, android.util.AttributeSet, boolean) (LayoutInflater.java:790)
2020-06-19 15:01:29.332 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.View android.view.LayoutInflater.createViewFromTag(android.view.View, java.lang.String, android.content.Context, android.util.AttributeSet) (LayoutInflater.java:730)
2020-06-19 15:01:29.332 31102-31102/com.inf4018.myapplication I/zygote:     at void android.view.LayoutInflater.rInflate(org.xmlpull.v1.XmlPullParser, android.view.View, android.content.Context, android.util.AttributeSet, boolean) (LayoutInflater.java:863)
2020-06-19 15:01:29.332 31102-31102/com.inf4018.myapplication I/zygote:     at void android.view.LayoutInflater.rInflateChildren(org.xmlpull.v1.XmlPullParser, android.view.View, android.util.AttributeSet, boolean) (LayoutInflater.java:824)
2020-06-19 15:01:29.332 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.View android.view.LayoutInflater.inflate(org.xmlpull.v1.XmlPullParser, android.view.ViewGroup, boolean) (LayoutInflater.java:515)
2020-06-19 15:01:29.332 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.View android.view.LayoutInflater.inflate(int, android.view.ViewGroup, boolean) (LayoutInflater.java:423)
2020-06-19 15:01:29.332 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.View android.view.LayoutInflater.inflate(int, android.view.ViewGroup) (LayoutInflater.java:374)
2020-06-19 15:01:29.332 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.ViewGroup androidx.appcompat.app.AppCompatDelegateImpl.createSubDecor() (AppCompatDelegateImpl.java:749)
2020-06-19 15:01:29.332 31102-31102/com.inf4018.myapplication I/zygote:     at void androidx.appcompat.app.AppCompatDelegateImpl.ensureSubDecor() (AppCompatDelegateImpl.java:659)
2020-06-19 15:01:29.332 31102-31102/com.inf4018.myapplication I/zygote:     at void androidx.appcompat.app.AppCompatDelegateImpl.setContentView(int) (AppCompatDelegateImpl.java:552)
2020-06-19 15:01:29.332 31102-31102/com.inf4018.myapplication I/zygote:     at void androidx.appcompat.app.AppCompatActivity.setContentView(int) (AppCompatActivity.java:161)
2020-06-19 15:01:29.332 31102-31102/com.inf4018.myapplication I/zygote:     at void com.inf4018.myapplication.MainActivity.onCreate(android.os.Bundle) (MainActivity.java:13)
2020-06-19 15:01:29.332 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.Activity.performCreate(android.os.Bundle, android.os.PersistableBundle) (Activity.java:7258)
2020-06-19 15:01:29.332 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.Activity.performCreate(android.os.Bundle) (Activity.java:7249)
2020-06-19 15:01:29.332 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.Instrumentation.callActivityOnCreate(android.app.Activity, android.os.Bundle) (Instrumentation.java:1222)
2020-06-19 15:01:29.332 31102-31102/com.inf4018.myapplication I/zygote:     at android.app.Activity android.app.ActivityThread.performLaunchActivity(android.app.ActivityThread$ActivityClientRecord, android.content.Intent) (ActivityThread.java:2927)
2020-06-19 15:01:29.332 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.ActivityThread.handleLaunchActivity(android.app.ActivityThread$ActivityClientRecord, android.content.Intent, java.lang.String) (ActivityThread.java:3059)
2020-06-19 15:01:29.332 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.ActivityThread.-wrap11(android.app.ActivityThread, android.app.ActivityThread$ActivityClientRecord, android.content.Intent, java.lang.String) (ActivityThread.java:-1)
2020-06-19 15:01:29.332 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.ActivityThread$H.handleMessage(android.os.Message) (ActivityThread.java:1724)
2020-06-19 15:01:29.332 31102-31102/com.inf4018.myapplication I/zygote:     at void android.os.Handler.dispatchMessage(android.os.Message) (Handler.java:106)
2020-06-19 15:01:29.332 31102-31102/com.inf4018.myapplication I/zygote:     at void android.os.Looper.loop() (Looper.java:164)
2020-06-19 15:01:29.332 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.ActivityThread.main(java.lang.String[]) (ActivityThread.java:7000)
2020-06-19 15:01:29.332 31102-31102/com.inf4018.myapplication I/zygote:     at java.lang.Object java.lang.reflect.Method.invoke(java.lang.Object, java.lang.Object[]) (Method.java:-2)
2020-06-19 15:01:29.332 31102-31102/com.inf4018.myapplication I/zygote:     at void com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run() (RuntimeInit.java:441)
2020-06-19 15:01:29.332 31102-31102/com.inf4018.myapplication I/zygote:     at void com.android.internal.os.ZygoteInit.main(java.lang.String[]) (ZygoteInit.java:1408)
2020-06-19 15:01:29.332 31102-31102/com.inf4018.myapplication I/zygote: Caused by: java.lang.ClassNotFoundException: Didn't find class "android.view.View$OnUnhandledKeyEventListener" on path: DexPathList[[zip file "/data/app/com.inf4018.myapplication-wEV0ozNFKbpYKsw16DaiBA==/base.apk"],nativeLibraryDirectories=[/data/app/com.inf4018.myapplication-wEV0ozNFKbpYKsw16DaiBA==/lib/arm, /system/lib, /vendor/lib]]
2020-06-19 15:01:29.332 31102-31102/com.inf4018.myapplication I/zygote:     at java.lang.Class dalvik.system.BaseDexClassLoader.findClass(java.lang.String) (BaseDexClassLoader.java:125)
2020-06-19 15:01:29.332 31102-31102/com.inf4018.myapplication I/zygote:     at java.lang.Class java.lang.ClassLoader.loadClass(java.lang.String, boolean) (ClassLoader.java:379)
2020-06-19 15:01:29.332 31102-31102/com.inf4018.myapplication I/zygote:     at java.lang.Class java.lang.ClassLoader.loadClass(java.lang.String) (ClassLoader.java:312)
2020-06-19 15:01:29.332 31102-31102/com.inf4018.myapplication I/zygote:     at void androidx.core.view.ViewCompat.setBackground(android.view.View, android.graphics.drawable.Drawable) (ViewCompat.java:2559)
2020-06-19 15:01:29.332 31102-31102/com.inf4018.myapplication I/zygote:     at void androidx.appcompat.widget.ActionBarContainer.<init>(android.content.Context, android.util.AttributeSet) (ActionBarContainer.java:63)
2020-06-19 15:01:29.332 31102-31102/com.inf4018.myapplication I/zygote:     at java.lang.Object java.lang.reflect.Constructor.newInstance0(java.lang.Object[]) (Constructor.java:-2)
2020-06-19 15:01:29.333 31102-31102/com.inf4018.myapplication I/zygote:     at java.lang.Object java.lang.reflect.Constructor.newInstance(java.lang.Object[]) (Constructor.java:334)
2020-06-19 15:01:29.333 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.View android.view.LayoutInflater.createView(java.lang.String, java.lang.String, android.util.AttributeSet) (LayoutInflater.java:647)
2020-06-19 15:01:29.333 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.View android.view.LayoutInflater.createViewFromTag(android.view.View, java.lang.String, android.content.Context, android.util.AttributeSet, boolean) (LayoutInflater.java:790)
2020-06-19 15:01:29.333 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.View android.view.LayoutInflater.createViewFromTag(android.view.View, java.lang.String, android.content.Context, android.util.AttributeSet) (LayoutInflater.java:730)
2020-06-19 15:01:29.333 31102-31102/com.inf4018.myapplication I/zygote:     at void android.view.LayoutInflater.rInflate(org.xmlpull.v1.XmlPullParser, android.view.View, android.content.Context, android.util.AttributeSet, boolean) (LayoutInflater.java:863)
2020-06-19 15:01:29.333 31102-31102/com.inf4018.myapplication I/zygote:     at void android.view.LayoutInflater.rInflateChildren(org.xmlpull.v1.XmlPullParser, android.view.View, android.util.AttributeSet, boolean) (LayoutInflater.java:824)
2020-06-19 15:01:29.333 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.View android.view.LayoutInflater.inflate(org.xmlpull.v1.XmlPullParser, android.view.ViewGroup, boolean) (LayoutInflater.java:515)
2020-06-19 15:01:29.333 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.View android.view.LayoutInflater.inflate(int, android.view.ViewGroup, boolean) (LayoutInflater.java:423)
2020-06-19 15:01:29.333 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.View android.view.LayoutInflater.inflate(int, android.view.ViewGroup) (LayoutInflater.java:374)
2020-06-19 15:01:29.333 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.ViewGroup androidx.appcompat.app.AppCompatDelegateImpl.createSubDecor() (AppCompatDelegateImpl.java:749)
2020-06-19 15:01:29.333 31102-31102/com.inf4018.myapplication I/zygote:     at void androidx.appcompat.app.AppCompatDelegateImpl.ensureSubDecor() (AppCompatDelegateImpl.java:659)
2020-06-19 15:01:29.333 31102-31102/com.inf4018.myapplication I/zygote:     at void androidx.appcompat.app.AppCompatDelegateImpl.setContentView(int) (AppCompatDelegateImpl.java:552)
2020-06-19 15:01:29.333 31102-31102/com.inf4018.myapplication I/zygote:     at void androidx.appcompat.app.AppCompatActivity.setContentView(int) (AppCompatActivity.java:161)
2020-06-19 15:01:29.333 31102-31102/com.inf4018.myapplication I/zygote:     at void com.inf4018.myapplication.MainActivity.onCreate(android.os.Bundle) (MainActivity.java:13)
2020-06-19 15:01:29.333 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.Activity.performCreate(android.os.Bundle, android.os.PersistableBundle) (Activity.java:7258)
2020-06-19 15:01:29.333 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.Activity.performCreate(android.os.Bundle) (Activity.java:7249)
2020-06-19 15:01:29.333 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.Instrumentation.callActivityOnCreate(android.app.Activity, android.os.Bundle) (Instrumentation.java:1222)
2020-06-19 15:01:29.333 31102-31102/com.inf4018.myapplication I/zygote:     at android.app.Activity android.app.ActivityThread.performLaunchActivity(android.app.ActivityThread$ActivityClientRecord, android.content.Intent) (ActivityThread.java:2927)
2020-06-19 15:01:29.333 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.ActivityThread.handleLaunchActivity(android.app.ActivityThread$ActivityClientRecord, android.content.Intent, java.lang.String) (ActivityThread.java:3059)
2020-06-19 15:01:29.333 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.ActivityThread.-wrap11(android.app.ActivityThread, android.app.ActivityThread$ActivityClientRecord, android.content.Intent, java.lang.String) (ActivityThread.java:-1)
2020-06-19 15:01:29.333 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.ActivityThread$H.handleMessage(android.os.Message) (ActivityThread.java:1724)
2020-06-19 15:01:29.333 31102-31102/com.inf4018.myapplication I/zygote:     at void android.os.Handler.dispatchMessage(android.os.Message) (Handler.java:106)
2020-06-19 15:01:29.333 31102-31102/com.inf4018.myapplication I/zygote:     at void android.os.Looper.loop() (Looper.java:164)
2020-06-19 15:01:29.333 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.ActivityThread.main(java.lang.String[]) (ActivityThread.java:7000)
2020-06-19 15:01:29.333 31102-31102/com.inf4018.myapplication I/zygote:     at java.lang.Object java.lang.reflect.Method.invoke(java.lang.Object, java.lang.Object[]) (Method.java:-2)
2020-06-19 15:01:29.333 31102-31102/com.inf4018.myapplication I/zygote:     at void com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run() (RuntimeInit.java:441)
2020-06-19 15:01:29.333 31102-31102/com.inf4018.myapplication I/zygote:     at void com.android.internal.os.ZygoteInit.main(java.lang.String[]) (ZygoteInit.java:1408)
2020-06-19 15:01:29.334 31102-31102/com.inf4018.myapplication I/zygote: Rejecting re-init on previously-failed class java.lang.Class<androidx.core.view.ViewCompat$2>: java.lang.NoClassDefFoundError: Failed resolution of: Landroid/view/View$OnUnhandledKeyEventListener;
2020-06-19 15:01:29.334 31102-31102/com.inf4018.myapplication I/zygote:     at void androidx.core.view.ViewCompat.setBackground(android.view.View, android.graphics.drawable.Drawable) (ViewCompat.java:2559)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at void androidx.appcompat.widget.ActionBarContainer.<init>(android.content.Context, android.util.AttributeSet) (ActionBarContainer.java:63)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at java.lang.Object java.lang.reflect.Constructor.newInstance0(java.lang.Object[]) (Constructor.java:-2)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at java.lang.Object java.lang.reflect.Constructor.newInstance(java.lang.Object[]) (Constructor.java:334)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.View android.view.LayoutInflater.createView(java.lang.String, java.lang.String, android.util.AttributeSet) (LayoutInflater.java:647)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.View android.view.LayoutInflater.createViewFromTag(android.view.View, java.lang.String, android.content.Context, android.util.AttributeSet, boolean) (LayoutInflater.java:790)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.View android.view.LayoutInflater.createViewFromTag(android.view.View, java.lang.String, android.content.Context, android.util.AttributeSet) (LayoutInflater.java:730)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at void android.view.LayoutInflater.rInflate(org.xmlpull.v1.XmlPullParser, android.view.View, android.content.Context, android.util.AttributeSet, boolean) (LayoutInflater.java:863)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at void android.view.LayoutInflater.rInflateChildren(org.xmlpull.v1.XmlPullParser, android.view.View, android.util.AttributeSet, boolean) (LayoutInflater.java:824)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.View android.view.LayoutInflater.inflate(org.xmlpull.v1.XmlPullParser, android.view.ViewGroup, boolean) (LayoutInflater.java:515)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.View android.view.LayoutInflater.inflate(int, android.view.ViewGroup, boolean) (LayoutInflater.java:423)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.View android.view.LayoutInflater.inflate(int, android.view.ViewGroup) (LayoutInflater.java:374)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.ViewGroup androidx.appcompat.app.AppCompatDelegateImpl.createSubDecor() (AppCompatDelegateImpl.java:749)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at void androidx.appcompat.app.AppCompatDelegateImpl.ensureSubDecor() (AppCompatDelegateImpl.java:659)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at void androidx.appcompat.app.AppCompatDelegateImpl.setContentView(int) (AppCompatDelegateImpl.java:552)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at void androidx.appcompat.app.AppCompatActivity.setContentView(int) (AppCompatActivity.java:161)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at void com.inf4018.myapplication.MainActivity.onCreate(android.os.Bundle) (MainActivity.java:13)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.Activity.performCreate(android.os.Bundle, android.os.PersistableBundle) (Activity.java:7258)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.Activity.performCreate(android.os.Bundle) (Activity.java:7249)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.Instrumentation.callActivityOnCreate(android.app.Activity, android.os.Bundle) (Instrumentation.java:1222)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at android.app.Activity android.app.ActivityThread.performLaunchActivity(android.app.ActivityThread$ActivityClientRecord, android.content.Intent) (ActivityThread.java:2927)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.ActivityThread.handleLaunchActivity(android.app.ActivityThread$ActivityClientRecord, android.content.Intent, java.lang.String) (ActivityThread.java:3059)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.ActivityThread.-wrap11(android.app.ActivityThread, android.app.ActivityThread$ActivityClientRecord, android.content.Intent, java.lang.String) (ActivityThread.java:-1)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.ActivityThread$H.handleMessage(android.os.Message) (ActivityThread.java:1724)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at void android.os.Handler.dispatchMessage(android.os.Message) (Handler.java:106)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at void android.os.Looper.loop() (Looper.java:164)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.ActivityThread.main(java.lang.String[]) (ActivityThread.java:7000)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at java.lang.Object java.lang.reflect.Method.invoke(java.lang.Object, java.lang.Object[]) (Method.java:-2)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at void com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run() (RuntimeInit.java:441)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at void com.android.internal.os.ZygoteInit.main(java.lang.String[]) (ZygoteInit.java:1408)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote: Caused by: java.lang.ClassNotFoundException: Didn't find class "android.view.View$OnUnhandledKeyEventListener" on path: DexPathList[[zip file "/data/app/com.inf4018.myapplication-wEV0ozNFKbpYKsw16DaiBA==/base.apk"],nativeLibraryDirectories=[/data/app/com.inf4018.myapplication-wEV0ozNFKbpYKsw16DaiBA==/lib/arm, /system/lib, /vendor/lib]]
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at java.lang.Class dalvik.system.BaseDexClassLoader.findClass(java.lang.String) (BaseDexClassLoader.java:125)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at java.lang.Class java.lang.ClassLoader.loadClass(java.lang.String, boolean) (ClassLoader.java:379)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at java.lang.Class java.lang.ClassLoader.loadClass(java.lang.String) (ClassLoader.java:312)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at void androidx.core.view.ViewCompat.setBackground(android.view.View, android.graphics.drawable.Drawable) (ViewCompat.java:2559)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at void androidx.appcompat.widget.ActionBarContainer.<init>(android.content.Context, android.util.AttributeSet) (ActionBarContainer.java:63)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at java.lang.Object java.lang.reflect.Constructor.newInstance0(java.lang.Object[]) (Constructor.java:-2)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at java.lang.Object java.lang.reflect.Constructor.newInstance(java.lang.Object[]) (Constructor.java:334)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.View android.view.LayoutInflater.createView(java.lang.String, java.lang.String, android.util.AttributeSet) (LayoutInflater.java:647)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.View android.view.LayoutInflater.createViewFromTag(android.view.View, java.lang.String, android.content.Context, android.util.AttributeSet, boolean) (LayoutInflater.java:790)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.View android.view.LayoutInflater.createViewFromTag(android.view.View, java.lang.String, android.content.Context, android.util.AttributeSet) (LayoutInflater.java:730)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at void android.view.LayoutInflater.rInflate(org.xmlpull.v1.XmlPullParser, android.view.View, android.content.Context, android.util.AttributeSet, boolean) (LayoutInflater.java:863)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at void android.view.LayoutInflater.rInflateChildren(org.xmlpull.v1.XmlPullParser, android.view.View, android.util.AttributeSet, boolean) (LayoutInflater.java:824)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.View android.view.LayoutInflater.inflate(org.xmlpull.v1.XmlPullParser, android.view.ViewGroup, boolean) (LayoutInflater.java:515)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.View android.view.LayoutInflater.inflate(int, android.view.ViewGroup, boolean) (LayoutInflater.java:423)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.View android.view.LayoutInflater.inflate(int, android.view.ViewGroup) (LayoutInflater.java:374)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.ViewGroup androidx.appcompat.app.AppCompatDelegateImpl.createSubDecor() (AppCompatDelegateImpl.java:749)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at void androidx.appcompat.app.AppCompatDelegateImpl.ensureSubDecor() (AppCompatDelegateImpl.java:659)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at void androidx.appcompat.app.AppCompatDelegateImpl.setContentView(int) (AppCompatDelegateImpl.java:552)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at void androidx.appcompat.app.AppCompatActivity.setContentView(int) (AppCompatActivity.java:161)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at void com.inf4018.myapplication.MainActivity.onCreate(android.os.Bundle) (MainActivity.java:13)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.Activity.performCreate(android.os.Bundle, android.os.PersistableBundle) (Activity.java:7258)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.Activity.performCreate(android.os.Bundle) (Activity.java:7249)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.Instrumentation.callActivityOnCreate(android.app.Activity, android.os.Bundle) (Instrumentation.java:1222)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at android.app.Activity android.app.ActivityThread.performLaunchActivity(android.app.ActivityThread$ActivityClientRecord, android.content.Intent) (ActivityThread.java:2927)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.ActivityThread.handleLaunchActivity(android.app.ActivityThread$ActivityClientRecord, android.content.Intent, java.lang.String) (ActivityThread.java:3059)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.ActivityThread.-wrap11(android.app.ActivityThread, android.app.ActivityThread$ActivityClientRecord, android.content.Intent, java.lang.String) (ActivityThread.java:-1)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.ActivityThread$H.handleMessage(android.os.Message) (ActivityThread.java:1724)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at void android.os.Handler.dispatchMessage(android.os.Message) (Handler.java:106)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at void android.os.Looper.loop() (Looper.java:164)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.ActivityThread.main(java.lang.String[]) (ActivityThread.java:7000)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at java.lang.Object java.lang.reflect.Method.invoke(java.lang.Object, java.lang.Object[]) (Method.java:-2)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at void com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run() (RuntimeInit.java:441)
2020-06-19 15:01:29.335 31102-31102/com.inf4018.myapplication I/zygote:     at void com.android.internal.os.ZygoteInit.main(java.lang.String[]) (ZygoteInit.java:1408)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote: Rejecting re-init on previously-failed class java.lang.Class<androidx.core.view.ViewCompat$2>: java.lang.NoClassDefFoundError: Failed resolution of: Landroid/view/View$OnUnhandledKeyEventListener;
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at void androidx.core.view.ViewCompat.setBackground(android.view.View, android.graphics.drawable.Drawable) (ViewCompat.java:2559)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at void androidx.appcompat.widget.ActionBarContainer.<init>(android.content.Context, android.util.AttributeSet) (ActionBarContainer.java:63)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at java.lang.Object java.lang.reflect.Constructor.newInstance0(java.lang.Object[]) (Constructor.java:-2)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at java.lang.Object java.lang.reflect.Constructor.newInstance(java.lang.Object[]) (Constructor.java:334)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.View android.view.LayoutInflater.createView(java.lang.String, java.lang.String, android.util.AttributeSet) (LayoutInflater.java:647)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.View android.view.LayoutInflater.createViewFromTag(android.view.View, java.lang.String, android.content.Context, android.util.AttributeSet, boolean) (LayoutInflater.java:790)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.View android.view.LayoutInflater.createViewFromTag(android.view.View, java.lang.String, android.content.Context, android.util.AttributeSet) (LayoutInflater.java:730)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at void android.view.LayoutInflater.rInflate(org.xmlpull.v1.XmlPullParser, android.view.View, android.content.Context, android.util.AttributeSet, boolean) (LayoutInflater.java:863)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at void android.view.LayoutInflater.rInflateChildren(org.xmlpull.v1.XmlPullParser, android.view.View, android.util.AttributeSet, boolean) (LayoutInflater.java:824)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.View android.view.LayoutInflater.inflate(org.xmlpull.v1.XmlPullParser, android.view.ViewGroup, boolean) (LayoutInflater.java:515)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.View android.view.LayoutInflater.inflate(int, android.view.ViewGroup, boolean) (LayoutInflater.java:423)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.View android.view.LayoutInflater.inflate(int, android.view.ViewGroup) (LayoutInflater.java:374)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.ViewGroup androidx.appcompat.app.AppCompatDelegateImpl.createSubDecor() (AppCompatDelegateImpl.java:749)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at void androidx.appcompat.app.AppCompatDelegateImpl.ensureSubDecor() (AppCompatDelegateImpl.java:659)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at void androidx.appcompat.app.AppCompatDelegateImpl.setContentView(int) (AppCompatDelegateImpl.java:552)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at void androidx.appcompat.app.AppCompatActivity.setContentView(int) (AppCompatActivity.java:161)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at void com.inf4018.myapplication.MainActivity.onCreate(android.os.Bundle) (MainActivity.java:13)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.Activity.performCreate(android.os.Bundle, android.os.PersistableBundle) (Activity.java:7258)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.Activity.performCreate(android.os.Bundle) (Activity.java:7249)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.Instrumentation.callActivityOnCreate(android.app.Activity, android.os.Bundle) (Instrumentation.java:1222)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at android.app.Activity android.app.ActivityThread.performLaunchActivity(android.app.ActivityThread$ActivityClientRecord, android.content.Intent) (ActivityThread.java:2927)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.ActivityThread.handleLaunchActivity(android.app.ActivityThread$ActivityClientRecord, android.content.Intent, java.lang.String) (ActivityThread.java:3059)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.ActivityThread.-wrap11(android.app.ActivityThread, android.app.ActivityThread$ActivityClientRecord, android.content.Intent, java.lang.String) (ActivityThread.java:-1)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.ActivityThread$H.handleMessage(android.os.Message) (ActivityThread.java:1724)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at void android.os.Handler.dispatchMessage(android.os.Message) (Handler.java:106)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at void android.os.Looper.loop() (Looper.java:164)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.ActivityThread.main(java.lang.String[]) (ActivityThread.java:7000)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at java.lang.Object java.lang.reflect.Method.invoke(java.lang.Object, java.lang.Object[]) (Method.java:-2)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at void com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run() (RuntimeInit.java:441)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at void com.android.internal.os.ZygoteInit.main(java.lang.String[]) (ZygoteInit.java:1408)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote: Caused by: java.lang.ClassNotFoundException: Didn't find class "android.view.View$OnUnhandledKeyEventListener" on path: DexPathList[[zip file "/data/app/com.inf4018.myapplication-wEV0ozNFKbpYKsw16DaiBA==/base.apk"],nativeLibraryDirectories=[/data/app/com.inf4018.myapplication-wEV0ozNFKbpYKsw16DaiBA==/lib/arm, /system/lib, /vendor/lib]]
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at java.lang.Class dalvik.system.BaseDexClassLoader.findClass(java.lang.String) (BaseDexClassLoader.java:125)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at java.lang.Class java.lang.ClassLoader.loadClass(java.lang.String, boolean) (ClassLoader.java:379)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at java.lang.Class java.lang.ClassLoader.loadClass(java.lang.String) (ClassLoader.java:312)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at void androidx.core.view.ViewCompat.setBackground(android.view.View, android.graphics.drawable.Drawable) (ViewCompat.java:2559)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at void androidx.appcompat.widget.ActionBarContainer.<init>(android.content.Context, android.util.AttributeSet) (ActionBarContainer.java:63)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at java.lang.Object java.lang.reflect.Constructor.newInstance0(java.lang.Object[]) (Constructor.java:-2)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at java.lang.Object java.lang.reflect.Constructor.newInstance(java.lang.Object[]) (Constructor.java:334)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.View android.view.LayoutInflater.createView(java.lang.String, java.lang.String, android.util.AttributeSet) (LayoutInflater.java:647)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.View android.view.LayoutInflater.createViewFromTag(android.view.View, java.lang.String, android.content.Context, android.util.AttributeSet, boolean) (LayoutInflater.java:790)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.View android.view.LayoutInflater.createViewFromTag(android.view.View, java.lang.String, android.content.Context, android.util.AttributeSet) (LayoutInflater.java:730)
2020-06-19 15:01:29.337 31102-31102/com.inf4018.myapplication I/zygote:     at void android.view.LayoutInflater.rInflate(org.xmlpull.v1.XmlPullParser, android.view.View, android.content.Context, android.util.AttributeSet, boolean) (LayoutInflater.java:863)
2020-06-19 15:01:29.341 31102-31102/com.inf4018.myapplication I/zygote:     at void android.view.LayoutInflater.rInflateChildren(org.xmlpull.v1.XmlPullParser, android.view.View, android.util.AttributeSet, boolean) (LayoutInflater.java:824)
2020-06-19 15:01:29.341 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.View android.view.LayoutInflater.inflate(org.xmlpull.v1.XmlPullParser, android.view.ViewGroup, boolean) (LayoutInflater.java:515)
2020-06-19 15:01:29.341 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.View android.view.LayoutInflater.inflate(int, android.view.ViewGroup, boolean) (LayoutInflater.java:423)
2020-06-19 15:01:29.341 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.View android.view.LayoutInflater.inflate(int, android.view.ViewGroup) (LayoutInflater.java:374)
2020-06-19 15:01:29.341 31102-31102/com.inf4018.myapplication I/zygote:     at android.view.ViewGroup androidx.appcompat.app.AppCompatDelegateImpl.createSubDecor() (AppCompatDelegateImpl.java:749)
2020-06-19 15:01:29.341 31102-31102/com.inf4018.myapplication I/zygote:     at void androidx.appcompat.app.AppCompatDelegateImpl.ensureSubDecor() (AppCompatDelegateImpl.java:659)
2020-06-19 15:01:29.341 31102-31102/com.inf4018.myapplication I/zygote:     at void androidx.appcompat.app.AppCompatDelegateImpl.setContentView(int) (AppCompatDelegateImpl.java:552)
2020-06-19 15:01:29.341 31102-31102/com.inf4018.myapplication I/zygote:     at void androidx.appcompat.app.AppCompatActivity.setContentView(int) (AppCompatActivity.java:161)
2020-06-19 15:01:29.342 31102-31102/com.inf4018.myapplication I/zygote:     at void com.inf4018.myapplication.MainActivity.onCreate(android.os.Bundle) (MainActivity.java:13)
2020-06-19 15:01:29.342 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.Activity.performCreate(android.os.Bundle, android.os.PersistableBundle) (Activity.java:7258)
2020-06-19 15:01:29.342 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.Activity.performCreate(android.os.Bundle) (Activity.java:7249)
2020-06-19 15:01:29.342 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.Instrumentation.callActivityOnCreate(android.app.Activity, android.os.Bundle) (Instrumentation.java:1222)
2020-06-19 15:01:29.342 31102-31102/com.inf4018.myapplication I/zygote:     at android.app.Activity android.app.ActivityThread.performLaunchActivity(android.app.ActivityThread$ActivityClientRecord, android.content.Intent) (ActivityThread.java:2927)
2020-06-19 15:01:29.342 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.ActivityThread.handleLaunchActivity(android.app.ActivityThread$ActivityClientRecord, android.content.Intent, java.lang.String) (ActivityThread.java:3059)
2020-06-19 15:01:29.342 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.ActivityThread.-wrap11(android.app.ActivityThread, android.app.ActivityThread$ActivityClientRecord, android.content.Intent, java.lang.String) (ActivityThread.java:-1)
2020-06-19 15:01:29.342 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.ActivityThread$H.handleMessage(android.os.Message) (ActivityThread.java:1724)
2020-06-19 15:01:29.342 31102-31102/com.inf4018.myapplication I/zygote:     at void android.os.Handler.dispatchMessage(android.os.Message) (Handler.java:106)
2020-06-19 15:01:29.342 31102-31102/com.inf4018.myapplication I/zygote:     at void android.os.Looper.loop() (Looper.java:164)
2020-06-19 15:01:29.342 31102-31102/com.inf4018.myapplication I/zygote:     at void android.app.ActivityThread.main(java.lang.String[]) (ActivityThread.java:7000)
2020-06-19 15:01:29.342 31102-31102/com.inf4018.myapplication I/zygote:     at java.lang.Object java.lang.reflect.Method.invoke(java.lang.Object, java.lang.Object[]) (Method.java:-2)
2020-06-19 15:01:29.342 31102-31102/com.inf4018.myapplication I/zygote:     at void com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run() (RuntimeInit.java:441)
2020-06-19 15:01:29.342 31102-31102/com.inf4018.myapplication I/zygote:     at void com.android.internal.os.ZygoteInit.main(java.lang.String[]) (ZygoteInit.java:1408)
2020-06-19 15:01:29.497 31102-31102/com.inf4018.myapplication D/AndroidRuntime: Shutting down VM
 
 
    --------- beginning of crash
2020-06-19 15:01:29.501 31102-31102/com.inf4018.myapplication E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.inf4018.myapplication, PID: 31102
    java.lang.RuntimeException: Unable to start activity ComponentInfo{com.inf4018.myapplication/com.inf4018.myapplication.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void java.io.PrintWriter.println(java.lang.String)' on a null object reference
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2974)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3059)
        at android.app.ActivityThread.-wrap11(Unknown Source:0)
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1724)
        at android.os.Handler.dispatchMessage(Handler.java:106)
        at android.os.Looper.loop(Looper.java:164)
        at android.app.ActivityThread.main(ActivityThread.java:7000)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:441)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1408)
     Caused by: java.lang.NullPointerException: Attempt to invoke virtual method 'void java.io.PrintWriter.println(java.lang.String)' on a null object reference
        at com.inf4018.myapplication.Connecteur.sendMessage(Connecteur.java:24)
        at com.inf4018.myapplication.MainActivity.onCreate(MainActivity.java:16)
        at android.app.Activity.performCreate(Activity.java:7258)
        at android.app.Activity.performCreate(Activity.java:7249)
        at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1222)
        at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2927)
        at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3059)*
        at android.app.ActivityThread.-wrap11(Unknown Source:0)*
        at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1724)*
        at android.os.Handler.dispatchMessage(Handler.java:106)*
        at android.os.Looper.loop(Looper.java:164)*
        at android.app.ActivityThread.main(ActivityThread.java:7000)*
        at java.lang.reflect.Method.invoke(Native Method)*
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:441)*
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1408)*

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