Firebase Cloud Messaging does not work
<p>I'm trying to show a notification on my application. I created an application on Firebase console. Note: There is no error. When the application start after I send a message from Firebase console nothing appears. What's wrong here?</p>

<p><code>MyFireBaseInstaceIDService.java</code></p>

<pre><code>package com.example.hp.mesajlasma;
import android.util.Log;
import com.google.firebase.iid.FirebaseInstanceId;
import com.google.firebase.iid.FirebaseInstanceIdService;


public class MyFirebaseInstanceIDService extends FirebaseInstanceIdService {

private static final String TAG = "MyFirebaseIIDService";

/**
 * Called if InstanceID token is updated. This may occur if the security of
 * the previous token had been compromised. Note that this is called when the InstanceID token
 * is initially generated so this is where you would retrieve the token.
 */
// [START refresh_token]
@Override
public void onTokenRefresh() {
    // Get updated InstanceID token.
    String refreshedToken = FirebaseInstanceId.getInstance().getToken();
    Log.d(TAG, "Refreshed token: " + refreshedToken);

    // If you want to send messages to this application instance or
    // manage this apps subscriptions on the server side, send the
    // Instance ID token to your app server.
    sendRegistrationToServer(refreshedToken);
}
// [END refresh_token]

/**
 * Persist token to third-party servers.
 *
 * Modify this method to associate the user's FCM InstanceID token with any server-side account
 * maintained by your application.
 *
 * @param token The new token.
 */
private void sendRegistrationToServer(String token) {
    // TODO: Implement this method to send token to your app server.
}
}
</code></pre>

<p><code>MyFireBaseMessagingService.java</code></p>

<pre><code>package com.example.hp.mesajlasma;

import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.media.RingtoneManager;
import android.net.Uri;
import android.support.v4.app.NotificationCompat;
import android.util.Log;

import com.google.firebase.messaging.FirebaseMessagingService;
import com.google.firebase.messaging.RemoteMessage;

/*** Created by Belal on 5/27/2016.*/

public class MyFirebaseMessagingService extends FirebaseMessagingService {

private static final String TAG = "MyFirebaseMsgService";

/**
 * Called when message is received.
 *
 * @param remoteMessage Object representing the message received from Firebase Cloud Messaging.
 */
// [START receive_message]
@Override
public void onMessageReceived(RemoteMessage remoteMessage) {
    // [START_EXCLUDE]
    // There are two types of messages data messages and notification messages. Data messages are handled
    // here in onMessageReceived whether the app is in the foreground or background. Data messages are the type
    // traditionally used with GCM. Notification messages are only received here in onMessageReceived when the app
    // is in the foreground. When the app is in the background an automatically generated notification is displayed.
    // When the user taps on the notification they are returned to the app. Messages containing both notification
    // and data payloads are treated as notification messages. The Firebase console always sends notification
    // messages. For more see: https://firebase.google.com/docs/cloud-messaging/concept-options
    // [END_EXCLUDE]

    Log.d(TAG, "From: " + remoteMessage.getFrom());

    // Check if message contains a data payload.
    if (remoteMessage.getData().size() &gt; 0) {
        Log.d(TAG, "Message data payload: " + remoteMessage.getData());
    }

    // Check if message contains a notification payload.
    if (remoteMessage.getNotification() != null) {
        Log.d(TAG, "Message Notification Body: " + remoteMessage.getNotification().getBody());
    }

    // Also if you intend on generating your own notifications as a result of a received FCM
    // message, here is where that should be initiated. See sendNotification method below.
}
// [END receive_message]

/**
 * Create and show a simple notification containing the received FCM message.
 *
 * @param messageBody FCM message body received.
 */
private void sendNotification(String messageBody) {
    Intent intent = new Intent(this, MainActivity.class);
    intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
    PendingIntent pendingIntent = PendingIntent.getActivity(this, 0 /* Request code */, intent,
            PendingIntent.FLAG_ONE_SHOT);

    Uri defaultSoundUri= RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION);
    NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(this)
            .setSmallIcon(R.drawable.common_google_signin_btn_icon_dark_focused)
            .setContentTitle("FCM Message")
            .setContentText(messageBody)
            .setAutoCancel(true)
            .setSound(defaultSoundUri)
            .setContentIntent(pendingIntent);

    NotificationManager notificationManager =
            (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);

    notificationManager.notify(0 /* ID of notification */, notificationBuilder.build());
}
}
</code></pre>

<p><code>build.gradle</code></p>

<pre><code>// Top-level build file where you can add configuration options common to all sub-projects/modules.


buildscript {
repositories {
    jcenter()
}
dependencies {
    classpath 'com.android.tools.build:gradle:2.2.0-alpha5'
    classpath 'com.google.gms:google-services:3.0.0'

    // NOTE: Do not place your application dependencies here; they belong
    // in the individual module build.gradle files
}
}

allprojects {
repositories {
    jcenter()
}
}

task clean(type: Delete) {
delete rootProject.buildDir
}
</code></pre>

<p><code>AndroidManifest</code></p>

<pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt;
&lt;manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.hp.mesajlasma"&gt;

&lt;uses-permission android:name="android.permission.INTERNET"/&gt;


&lt;application
    android:allowBackup="true"
    android:icon="@mipmap/ic_launcher"
    android:label="@string/app_name"
    android:supportsRtl="true"
    android:theme="@style/AppTheme"&gt;
    &lt;activity android:name=".MainActivity"&gt;
        &lt;intent-filter&gt;
            &lt;action android:name="android.intent.action.MAIN" /&gt;

            &lt;category android:name="android.intent.category.LAUNCHER" /&gt;
        &lt;/intent-filter&gt;
    &lt;/activity&gt;

    &lt;!--
       Defining Services
   --&gt;
    &lt;service
        android:name=".MyFirebaseMessagingService"&gt;
        &lt;intent-filter&gt;
            &lt;action android:name="com.google.firebase.MESSAGING_EVENT"/&gt;
        &lt;/intent-filter&gt;
    &lt;/service&gt;

    &lt;service
        android:name=".MyFirebaseInstanceIDService"&gt;
        &lt;intent-filter&gt;
            &lt;action android:name="com.google.firebase.INSTANCE_ID_EVENT"/&gt;
        &lt;/intent-filter&gt;
    &lt;/service&gt;
&lt;/application&gt;

&lt;/manifest&gt;
</code></pre>

<p><code>build.gradle</code> (app)</p>

<pre><code>apply plugin: 'com.android.application'

android {
compileSdkVersion 23
buildToolsVersion "24.0.0"
defaultConfig {
    applicationId "com.example.hp.mesajlasma"
    minSdkVersion 15
    targetSdkVersion 23
    versionCode 1
    versionName "1.0"
    testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
}
buildTypes {
    release {
        minifyEnabled false
        proguardFiles getDefaultProguardFile('proguard-android.txt'),         'proguard-rules.pro'
    }
}
}

dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2',              {
    exclude group: 'com.android.support', module: 'support-annotations'
})
compile 'com.android.support:appcompat-v7:23.4.0'
compile 'com.android.support.constraint:constraint-layout:1.0.0-alpha5'
testCompile 'junit:junit:4.12'
compile 'com.google.firebase:firebase-messaging:9.0.0'
}
apply plugin: 'com.google.gms.google-services'
</code></pre>