diff --git a/app/src/main/java/com/nextcloud/talk/controllers/ProfileController.java b/app/src/main/java/com/nextcloud/talk/controllers/ProfileController.java
index 07f94bce2..96953dff9 100644
--- a/app/src/main/java/com/nextcloud/talk/controllers/ProfileController.java
+++ b/app/src/main/java/com/nextcloud/talk/controllers/ProfileController.java
@@ -65,7 +65,6 @@ import com.nextcloud.talk.utils.DisplayUtils;
 import com.nextcloud.talk.utils.bundle.BundleKeys;
 import com.nextcloud.talk.utils.database.user.UserUtils;
 
-import org.jetbrains.annotations.NotNull;
 import org.parceler.Parcels;
 
 import java.io.File;
@@ -183,17 +182,17 @@ public class ProfileController extends BaseController {
                             .observeOn(AndroidSchedulers.mainThread())
                             .subscribe(new Observer<UserProfileFieldsOverall>() {
                                 @Override
-                                public void onSubscribe(@NotNull Disposable d) {
+                                public void onSubscribe(@io.reactivex.annotations.NonNull Disposable d) {
                                 }
 
                                 @Override
-                                public void onNext(@NotNull UserProfileFieldsOverall userProfileFieldsOverall) {
+                                public void onNext(@io.reactivex.annotations.NonNull UserProfileFieldsOverall userProfileFieldsOverall) {
                                     editableFields = userProfileFieldsOverall.getOcs().getData();
                                     adapter.notifyDataSetChanged();
                                 }
 
                                 @Override
-                                public void onError(@NotNull Throwable e) {
+                                public void onError(@io.reactivex.annotations.NonNull Throwable e) {
                                     edit = false;
                                 }
 
@@ -243,11 +242,11 @@ public class ProfileController extends BaseController {
                         .observeOn(AndroidSchedulers.mainThread())
                         .subscribe(new Observer<GenericOverall>() {
                             @Override
-                            public void onSubscribe(@NotNull Disposable d) {
+                            public void onSubscribe(@NonNull Disposable d) {
                             }
 
                             @Override
-                            public void onNext(@NotNull GenericOverall genericOverall) {
+                            public void onNext(@NonNull GenericOverall genericOverall) {
                                 DisplayUtils.loadAvatarImage(
                                         currentUser,
                                         getActivity().findViewById(R.id.avatar_image),
@@ -255,7 +254,7 @@ public class ProfileController extends BaseController {
                             }
 
                             @Override
-                            public void onError(@NotNull Throwable e) {
+                            public void onError(@NonNull Throwable e) {
                                 Toast.makeText(getApplicationContext(), "Error", Toast.LENGTH_LONG).show();
                             }
 
diff --git a/app/src/main/java/com/nextcloud/talk/utils/PushUtils.java b/app/src/main/java/com/nextcloud/talk/utils/PushUtils.java
index 65a72f8d9..205b906ac 100644
--- a/app/src/main/java/com/nextcloud/talk/utils/PushUtils.java
+++ b/app/src/main/java/com/nextcloud/talk/utils/PushUtils.java
@@ -24,7 +24,7 @@ import android.content.Context;
 import android.text.TextUtils;
 import android.util.Base64;
 import android.util.Log;
-import autodagger.AutoInjector;
+
 import com.bluelinelabs.logansquare.LoganSquare;
 import com.nextcloud.talk.R;
 import com.nextcloud.talk.api.NcApi;
@@ -36,14 +36,24 @@ import com.nextcloud.talk.models.json.push.PushConfigurationState;
 import com.nextcloud.talk.models.json.push.PushRegistrationOverall;
 import com.nextcloud.talk.utils.database.user.UserUtils;
 import com.nextcloud.talk.utils.preferences.AppPreferences;
-import io.reactivex.Observer;
-import io.reactivex.disposables.Disposable;
-import io.reactivex.schedulers.Schedulers;
+
 import org.greenrobot.eventbus.EventBus;
 
-import javax.inject.Inject;
-import java.io.*;
-import java.security.*;
+import java.io.File;
+import java.io.FileInputStream;
+import java.io.FileNotFoundException;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.security.InvalidKeyException;
+import java.security.Key;
+import java.security.KeyFactory;
+import java.security.KeyPair;
+import java.security.KeyPairGenerator;
+import java.security.MessageDigest;
+import java.security.NoSuchAlgorithmException;
+import java.security.PublicKey;
+import java.security.Signature;
+import java.security.SignatureException;
 import java.security.spec.InvalidKeySpecException;
 import java.security.spec.PKCS8EncodedKeySpec;
 import java.security.spec.X509EncodedKeySpec;
@@ -51,6 +61,14 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
+import javax.inject.Inject;
+
+import autodagger.AutoInjector;
+import io.reactivex.Observer;
+import io.reactivex.annotations.NonNull;
+import io.reactivex.disposables.Disposable;
+import io.reactivex.schedulers.Schedulers;
+
 @AutoInjector(NextcloudTalkApplication.class)
 public class PushUtils {
     private static final String TAG = "PushUtils";
@@ -247,18 +265,17 @@ public class PushUtils {
 
                             credentials = ApiUtils.getCredentials(userEntity.getUsername(), userEntity.getToken());
 
-                            String finalCredentials = credentials;
                             ncApi.registerDeviceForNotificationsWithNextcloud(
                                     credentials,
                                     ApiUtils.getUrlNextcloudPush(userEntity.getBaseUrl()), queryMap)
                                     .subscribe(new Observer<PushRegistrationOverall>() {
                                         @Override
-                                        public void onSubscribe(Disposable d) {
+                                        public void onSubscribe(@NonNull Disposable d) {
 
                                         }
 
                                         @Override
-                                        public void onNext(PushRegistrationOverall pushRegistrationOverall) {
+                                        public void onNext(@NonNull PushRegistrationOverall pushRegistrationOverall) {
                                             Map<String, String> proxyMap = new HashMap<>();
                                             proxyMap.put("pushToken", token);
                                             proxyMap.put("deviceIdentifier", pushRegistrationOverall.getOcs().getData().
@@ -274,12 +291,12 @@ public class PushUtils {
                                                     .subscribeOn(Schedulers.io())
                                                     .subscribe(new Observer<Void>() {
                                                         @Override
-                                                        public void onSubscribe(Disposable d) {
+                                                        public void onSubscribe(@NonNull Disposable d) {
 
                                                         }
 
                                                         @Override
-                                                        public void onNext(Void aVoid) {
+                                                        public void onNext(@NonNull Void aVoid) {
                                                             PushConfigurationState pushConfigurationState =
                                                                     new PushConfigurationState();
                                                             pushConfigurationState.setPushToken(token);
@@ -332,7 +349,7 @@ public class PushUtils {
                                                         }
 
                                                         @Override
-                                                        public void onError(Throwable e) {
+                                                        public void onError(@NonNull Throwable e) {
                                                             eventBus.post(new EventStatus(userEntity.getId(),
                                                                     EventStatus.EventType.PUSH_REGISTRATION, false));
                                                         }
@@ -345,7 +362,7 @@ public class PushUtils {
                                         }
 
                                         @Override
-                                        public void onError(Throwable e) {
+                                        public void onError(@NonNull Throwable e) {
                                             eventBus.post(new EventStatus(userEntity.getId(),
                                                     EventStatus.EventType.PUSH_REGISTRATION, false));