Firebase notification not sending from Java code

Question

I can successfully send notifications from the Firebase console to my device, but when I try to do it from Java code, I get a very unhelpful error:

04-12 20:18:09.284 17549-17549/com.package.example W/System.err:       at com.package.example.FCMNotification.pushFCMNotification(FCMNotification.java:102)

Here is my FCMNotification Class

public class FCMNotification {
public final static String AUTH_KEY_FCM = "FCM_SERVERKEY";
public final static String API_URL_FCM = "https://fcm.googleapis.com/fcm/send";

public static void pushFCMNotification(String deviceToken, String title, String body)
        throws IOException, JSONException {
    String authKey = AUTH_KEY_FCM;   // You FCM AUTH key
    String FMCurl = API_URL_FCM;

    URL url = new URL(FMCurl);
    HttpURLConnection conn = (HttpURLConnection) url.openConnection();

    conn.setUseCaches(false);
    conn.setDoInput(true);
    conn.setDoOutput(true);

    conn.setRequestMethod("POST");
    conn.setRequestProperty("Authorization","key="+authKey);
    conn.setRequestProperty("Content-Type","application/json");

    JSONObject json = new JSONObject();
    json.put("to",deviceToken.trim());
    JSONObject info = new JSONObject();
    info.put("title", title);   // Notification title
    info.put("body", body); // Notification body
    json.put("notification", info);

    OutputStreamWriter wr = new OutputStreamWriter(conn.getOutputStream());
    wr.write(json.toString());
    wr.flush();
    conn.getInputStream();
  }
}

And I call this class in my activity like this

FCMNotification obj = new FCMNotification();
obj.pushFCMNotification("DEVICE_TOKEN", "TITLE", "BODY");

EDIT

My app might be having trouble connecting to firebase server itself, so I have included my manifest and Gradle:

Manifest:

    <manifest xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
package="com.package.example">

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
        android:name="com.google.firebase.messaging.default_notification_icon"
        android:resource="@drawable/globalicon" />
    <meta-data
        android:name="com.google.firebase.messaging.default_notification_color"
        android:resource="@color/cardview_shadow_start_color" />

    <service android:name="com.package.example.PushNotification"
        android:enabled="true"
        android:exported="true">
        <intent-filter>
            <action android:name="com.google.firebase.INSTANCE_ID_EVENT" />
        </intent-filter>
    </service>
    <service android:name="com.package.example.FCMService">
        <intent-filter>
            <action android:name="com.google.firebase.MESSAGING_EVENT" />
        </intent-filter>
    </service>

 </application>

</manifest>

Gradle:

     apply plugin: 'com.android.application'

android {
   packagingOptions {
    exclude 'META-INF/LICENSE'
    exclude 'META-INF/io.netty.versions.properties'
    exclude 'META-INF/INDEX.LIST'
   }

signingConfigs {
    config {
    }
}
compileSdkVersion rootProject.ext.compileSdkVersion
buildToolsVersion rootProject.ext.buildToolsVersion
defaultConfig {
    multiDexEnabled true
    applicationId "com.gespanet.global"
    minSdkVersion rootProject.ext.minSdkVersion
    targetSdkVersion rootProject.ext.targetSdkVersion
    versionCode 29
    versionName "1.2"
}
buildTypes {
    release {
        minifyEnabled false
        proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
    }
}
lintOptions {
    disable 'MissingTranslation'
    disable 'ExtraTranslation'
}
dexOptions {
    javaMaxHeapSize "4g"
}

repositories {
    mavenCentral()
}

dependencies {
    compile ('com.google.apis:google-api-services-translate:v2-rev49-1.22.0') {
        exclude group: 'com.google.guava'
    }
    compile ('com.google.cloud:google-cloud-translate:0.11.0-alpha') {
        exclude group: 'io.grpc', module: 'grpc-all'
        exclude group: 'com.google.protobuf', module: 'protobuf-java'
        exclude group: 'com.google.api-client', module: 'google-api-client-appengine'
    }
    compile 'com.google.android.gms:play-services:10.2.1'
    compile 'com.google.firebase:firebase-core:10.2.0'
    compile 'com.google.firebase:firebase-messaging:10.2.0'
    compile 'com.android.support:appcompat-v7:25.3.1'
    compile 'com.android.support:design:25.3.1'
    compile 'com.parse.bolts:bolts-tasks:1.3.0'
    compile 'com.parse:parse-android:1.13.0'
    compile 'com.android.support:multidex:1.0.1'
    compile 'com.facebook.android:facebook-android-sdk:4.+'

}

configurations.all {
    exclude group: 'org.json', module: 'json'
    resolutionStrategy.force 'com.google.code.findbugs:jsr305:1.3.9'
 }



}
apply plugin: 'com.google.gms.google-services'

FULL ERROR LOG CAT FROM TRY/CATCHEXCEPTION:

04-12 23:31:56.027 12815-12815/com.gespanet.global W/System.err: android.os.NetworkOnMainThreadException
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1273)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at java.net.InetAddress.lookupHostByName(InetAddress.java:431)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at java.net.InetAddress.getAllByNameImpl(InetAddress.java:252)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at java.net.InetAddress.getAllByName(InetAddress.java:215)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.Network$1.resolveInetAddresses(Network.java:29)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.http.RouteSelector.resetNextInetSocketAddress(RouteSelector.java:220)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.http.RouteSelector.nextProxy(RouteSelector.java:176)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.http.RouteSelector.next(RouteSelector.java:108)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.http.HttpEngine.createNextConnection(HttpEngine.java:500)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.http.HttpEngine.nextConnection(HttpEngine.java:483)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.http.HttpEngine.connect(HttpEngine.java:465)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java:371)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.huc.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:476)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.huc.HttpURLConnectionImpl.connect(HttpURLConnectionImpl.java:118)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.huc.HttpURLConnectionImpl.getOutputStream(HttpURLConnectionImpl.java:249)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.huc.DelegatingHttpsURLConnection.getOutputStream(DelegatingHttpsURLConnection.java:218)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.huc.HttpsURLConnectionImpl.getOutputStream(HttpsURLConnectionImpl.java:25)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at com.gespanet.global.FCMNotification.pushFCMNotification(FCMNotification.java:52)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at com.gespanet.global.IndividualFeed$214$1$1$3$1$2$1.done(IndividualFeed.java:6397)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at com.gespanet.global.IndividualFeed$214$1$1$3$1$2$1.done(IndividualFeed.java:6389)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at com.parse.ParseTaskUtils$2$1.run(ParseTaskUtils.java:116)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at android.os.Handler.handleCallback(Handler.java:739)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at android.os.Handler.dispatchMessage(Handler.java:95)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at android.os.Looper.loop(Looper.java:148)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at android.app.ActivityThread.main(ActivityThread.java:7223)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at java.lang.reflect.Method.invoke(Native Method)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err: java.lang.NullPointerException: Attempt to invoke interface method 'void com.android.okhttp.internal.http.Transport.writeRequestHeaders(com.android.okhttp.Request)' on a null object reference
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.http.HttpEngine.readResponse(HttpEngine.java:971)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.huc.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:482)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.huc.HttpURLConnectionImpl.getResponse(HttpURLConnectionImpl.java:418)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.huc.HttpURLConnectionImpl.getResponseCode(HttpURLConnectionImpl.java:540)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.huc.DelegatingHttpsURLConnection.getResponseCode(DelegatingHttpsURLConnection.java:105)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.huc.HttpsURLConnectionImpl.getResponseCode(HttpsURLConnectionImpl.java:25)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at com.gespanet.global.FCMNotification.pushFCMNotification(FCMNotification.java:64)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at com.gespanet.global.IndividualFeed$214$1$1$3$1$2$1.done(IndividualFeed.java:6397)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at com.gespanet.global.IndividualFeed$214$1$1$3$1$2$1.done(IndividualFeed.java:6389)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at com.parse.ParseTaskUtils$2$1.run(ParseTaskUtils.java:116)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at android.os.Handler.handleCallback(Handler.java:739)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at android.os.Handler.dispatchMessage(Handler.java:95)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at android.os.Looper.loop(Looper.java:148)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at android.app.ActivityThread.main(ActivityThread.java:7223)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at java.lang.reflect.Method.invoke(Native Method)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
04-12 23:31:56.037 12815-12815/com.gespanet.global W/System.err:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)
04-12 23:31:56.037 12815-12815/com.gespanet.global I/System.out: (HTTPLog)-Static: Hongbao
04-12 23:31:56.037 12815-12815/com.gespanet.global I/System.out: (HTTPLog)-Static: isSBSettingEnabled false
04-12 23:31:56.037 12815-12815/com.gespanet.global I/System.out: (HTTPLog)-Static: Hongbao
04-12 23:31:56.037 12815-12815/com.gespanet.global I/System.out: (HTTPLog)-Static: isSBSettingEnabled false
04-12 23:31:56.047 12815-12815/com.gespanet.global I/push: Error is here
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err: android.os.NetworkOnMainThreadException
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1273)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at java.net.InetAddress.lookupHostByName(InetAddress.java:431)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at java.net.InetAddress.getAllByNameImpl(InetAddress.java:252)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at java.net.InetAddress.getAllByName(InetAddress.java:215)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.Network$1.resolveInetAddresses(Network.java:29)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.http.RouteSelector.resetNextInetSocketAddress(RouteSelector.java:220)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.http.RouteSelector.nextProxy(RouteSelector.java:176)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.http.RouteSelector.next(RouteSelector.java:108)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.http.HttpEngine.createNextConnection(HttpEngine.java:500)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.http.HttpEngine.nextConnection(HttpEngine.java:483)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.http.HttpEngine.connect(HttpEngine.java:465)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java:371)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.huc.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:476)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.huc.HttpURLConnectionImpl.connect(HttpURLConnectionImpl.java:118)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.huc.HttpURLConnectionImpl.getOutputStream(HttpURLConnectionImpl.java:249)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.huc.DelegatingHttpsURLConnection.getOutputStream(DelegatingHttpsURLConnection.java:218)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.huc.HttpsURLConnectionImpl.getOutputStream(HttpsURLConnectionImpl.java:25)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at com.gespanet.global.FCMNotification.pushFCMNotification(FCMNotification.java:52)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at com.gespanet.global.IndividualFeed$214$1$1$3$1$2$1.done(IndividualFeed.java:6397)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at com.gespanet.global.IndividualFeed$214$1$1$3$1$2$1.done(IndividualFeed.java:6389)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at com.parse.ParseTaskUtils$2$1.run(ParseTaskUtils.java:116)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at android.os.Handler.handleCallback(Handler.java:739)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at android.os.Handler.dispatchMessage(Handler.java:95)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at android.os.Looper.loop(Looper.java:148)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at android.app.ActivityThread.main(ActivityThread.java:7223)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at java.lang.reflect.Method.invoke(Native Method)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err: java.lang.NullPointerException: Attempt to invoke interface method 'void com.android.okhttp.internal.http.Transport.writeRequestHeaders(com.android.okhttp.Request)' on a null object reference
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.http.HttpEngine.readResponse(HttpEngine.java:971)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.huc.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:482)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.huc.HttpURLConnectionImpl.getResponse(HttpURLConnectionImpl.java:418)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.huc.HttpURLConnectionImpl.getResponseCode(HttpURLConnectionImpl.java:540)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.huc.DelegatingHttpsURLConnection.getResponseCode(DelegatingHttpsURLConnection.java:105)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.huc.HttpsURLConnectionImpl.getResponseCode(HttpsURLConnectionImpl.java:25)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at com.gespanet.global.FCMNotification.pushFCMNotification(FCMNotification.java:64)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at com.gespanet.global.IndividualFeed$214$1$1$3$1$2$1.done(IndividualFeed.java:6397)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at com.gespanet.global.IndividualFeed$214$1$1$3$1$2$1.done(IndividualFeed.java:6389)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at com.parse.ParseTaskUtils$2$1.run(ParseTaskUtils.java:116)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at android.os.Handler.handleCallback(Handler.java:739)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at android.os.Handler.dispatchMessage(Handler.java:95)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at android.os.Looper.loop(Looper.java:148)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at android.app.ActivityThread.main(ActivityThread.java:7223)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at java.lang.reflect.Method.invoke(Native Method)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
04-12 23:31:56.047 12815-12815/com.gespanet.global W/System.err:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)
04-12 23:31:56.067 12815-12815/com.gespanet.global I/System.out: (HTTPLog)-Static: Hongbao
04-12 23:31:56.067 12815-12815/com.gespanet.global I/System.out: (HTTPLog)-Static: isSBSettingEnabled false
04-12 23:31:56.067 12815-12815/com.gespanet.global I/System.out: (HTTPLog)-Static: Hongbao
04-12 23:31:56.067 12815-12815/com.gespanet.global I/System.out: (HTTPLog)-Static: isSBSettingEnabled false
04-12 23:31:56.067 12815-12815/com.gespanet.global I/push: Error is here
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err: android.os.NetworkOnMainThreadException
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at android.os.StrictMode$AndroidBlockGuardPolicy.onNetwork(StrictMode.java:1273)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at java.net.InetAddress.lookupHostByName(InetAddress.java:431)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at java.net.InetAddress.getAllByNameImpl(InetAddress.java:252)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at java.net.InetAddress.getAllByName(InetAddress.java:215)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.Network$1.resolveInetAddresses(Network.java:29)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.http.RouteSelector.resetNextInetSocketAddress(RouteSelector.java:220)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.http.RouteSelector.nextProxy(RouteSelector.java:176)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.http.RouteSelector.next(RouteSelector.java:108)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.http.HttpEngine.createNextConnection(HttpEngine.java:500)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.http.HttpEngine.nextConnection(HttpEngine.java:483)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.http.HttpEngine.connect(HttpEngine.java:465)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.http.HttpEngine.sendRequest(HttpEngine.java:371)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.huc.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:476)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.huc.HttpURLConnectionImpl.connect(HttpURLConnectionImpl.java:118)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.huc.HttpURLConnectionImpl.getOutputStream(HttpURLConnectionImpl.java:249)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.huc.DelegatingHttpsURLConnection.getOutputStream(DelegatingHttpsURLConnection.java:218)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.huc.HttpsURLConnectionImpl.getOutputStream(HttpsURLConnectionImpl.java:25)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at com.gespanet.global.FCMNotification.pushFCMNotification(FCMNotification.java:52)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at com.gespanet.global.IndividualFeed$214$1$1$3$1$1$1.done(IndividualFeed.java:6366)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at com.gespanet.global.IndividualFeed$214$1$1$3$1$1$1.done(IndividualFeed.java:6358)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at com.parse.ParseTaskUtils$2$1.run(ParseTaskUtils.java:116)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at android.os.Handler.handleCallback(Handler.java:739)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at android.os.Handler.dispatchMessage(Handler.java:95)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at android.os.Looper.loop(Looper.java:148)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at android.app.ActivityThread.main(ActivityThread.java:7223)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at java.lang.reflect.Method.invoke(Native Method)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err: java.lang.NullPointerException: Attempt to invoke interface method 'void com.android.okhttp.internal.http.Transport.writeRequestHeaders(com.android.okhttp.Request)' on a null object reference
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.http.HttpEngine.readResponse(HttpEngine.java:971)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.huc.HttpURLConnectionImpl.execute(HttpURLConnectionImpl.java:482)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.huc.HttpURLConnectionImpl.getResponse(HttpURLConnectionImpl.java:418)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.huc.HttpURLConnectionImpl.getResponseCode(HttpURLConnectionImpl.java:540)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.huc.DelegatingHttpsURLConnection.getResponseCode(DelegatingHttpsURLConnection.java:105)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at com.android.okhttp.internal.huc.HttpsURLConnectionImpl.getResponseCode(HttpsURLConnectionImpl.java:25)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at com.gespanet.global.FCMNotification.pushFCMNotification(FCMNotification.java:64)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at com.gespanet.global.IndividualFeed$214$1$1$3$1$1$1.done(IndividualFeed.java:6366)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at com.gespanet.global.IndividualFeed$214$1$1$3$1$1$1.done(IndividualFeed.java:6358)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at com.parse.ParseTaskUtils$2$1.run(ParseTaskUtils.java:116)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at android.os.Handler.handleCallback(Handler.java:739)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at android.os.Handler.dispatchMessage(Handler.java:95)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at android.os.Looper.loop(Looper.java:148)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at android.app.ActivityThread.main(ActivityThread.java:7223)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at java.lang.reflect.Method.invoke(Native Method)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
04-12 23:31:56.067 12815-12815/com.gespanet.global W/System.err:     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)

what is the line 102 contains in `FCMNotification .java` class. May be your application is unable to connect to fire-base server due to a firewall. — Rajith Pemabandu, Apr 13 '17 at 00:44
suppose the `FCM_SERVERKEY` is a correct one. then I think probably there is a connection issue from your application to Firebase server. — Rajith Pemabandu, Apr 13 '17 at 00:50
I added my manifest and gradle. Any idea on what's causing the connection issue because the server key is correct. Maybe I have to generate a new one. What's your thoughts. @RajithPemabandu — grantespo, Apr 13 '17 at 01:07
Hi grant. It's hard to pinpoint what's throwing the error here. Is that the complete logs? If not, do post the complete one. If it is, try using a try-catch statement to help pinpoint where the error is coming from. — AL., Apr 13 '17 at 03:04
I added the Full error log from the try/catch exception. It's very long. @AL. — grantespo, Apr 13 '17 at 03:34
Thanks grant. It's pointing out a `NetworkOnMainThreadException`. Could you try putting the whole `pushFCMNotification` method in an `AsnycTask` as mentioned [here](http://stackoverflow.com/q/6343166/4625829)? — AL., Apr 13 '17 at 03:39

score 0 · Accepted Answer · answered Apr 13 '17 at 06:01

To Send a Notification with Java. Implement this class:

      public class FCMNotification {

// Method to send Notifications from server to client end.
public final static String AUTH_KEY_FCM = "YOUR_SERVERKEY";
public final static String API_URL_FCM = "https://fcm.googleapis.com/fcm/send";

public static void pushFCMNotification(final String DeviceIdKey, final String title, final String body) throws Exception {

    AsyncTask<Void, Void, Void> asyncTask = new AsyncTask<Void, Void, Void>() {
        @Override
        protected Void doInBackground(Void... voids) {
            BufferedReader in = null;


            String authKey = AUTH_KEY_FCM;   // You FCM AUTH key
            String FMCurl = API_URL_FCM;

            URL url = null;
            try {
                url = new URL(FMCurl);
            } catch (MalformedURLException e) {
                Log.i("yoyoyo", "error: 1");
                e.printStackTrace();
            }
            HttpURLConnection conn = null;
            try {
                conn = (HttpURLConnection) url.openConnection();
            } catch (IOException e) {
                Log.i("yoyoyo", "error: 2");
                e.printStackTrace();
            }

            conn.setUseCaches(false);
            conn.setDoInput(true);
            conn.setDoOutput(true);

            try {
                conn.setRequestMethod("POST");
            } catch (ProtocolException e) {
                Log.i("yoyoyo", "error: 3");
                e.printStackTrace();
            }
            conn.setRequestProperty("Authorization","key="+authKey);
            conn.setRequestProperty("Content-Type","application/json");

            JSONObject json = new JSONObject();
            try {
                json.put("to",DeviceIdKey.trim());
            } catch (JSONException e) {
                Log.i("yoyoyo", "error: 4");
                e.printStackTrace();
            }
            JSONObject info = new JSONObject();
            try {
                info.put("title", title);   // Notification title
            } catch (JSONException e) {
                Log.i("yoyoyo", "error: 5");
                e.printStackTrace();
            }
            try {
                info.put("body", body); // Notification body
            } catch (JSONException e) {
                Log.i("yoyoyo", "error: 6");
                e.printStackTrace();
            }
            try {
                json.put("notification", info);
            } catch (JSONException e) {
                Log.i("yoyoyo", "error: 7");
                e.printStackTrace();
            }

            OutputStreamWriter wr = null;
            try {
                wr = new OutputStreamWriter(conn.getOutputStream());
            } catch (IOException e) {
                Log.i("yoyoyo", "error: 8");
                e.printStackTrace();
            }
            try {
                wr.write(json.toString());
            } catch (IOException e) {
                Log.i("yoyoyo", "error: 9");
                e.printStackTrace();
            }
            try {
                wr.flush();
            } catch (IOException e) {
                Log.i("yoyoyo", "error: 10");
                e.printStackTrace();
            }
            try {
                conn.getInputStream();
            } catch (IOException e) {
                Log.i("yoyoyo", "error: 11");
                e.printStackTrace();
            }

            return null;
        }
    };
    asyncTask.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR);



 }


}

Firebase notification not sending from Java code

1 Answers1