diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/GBApplication.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/GBApplication.java
index ec811229..baabf5d1 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/GBApplication.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/GBApplication.java
@@ -40,6 +40,7 @@ import java.io.File;
 import java.io.IOException;
 import java.util.HashSet;
 import java.util.List;
+import java.util.Set;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.locks.Lock;
 import java.util.concurrent.locks.ReentrantLock;
@@ -313,10 +314,23 @@ public class GBApplication extends Application {
         return NotificationManager.INTERRUPTION_FILTER_ALL;
     }
 
-    public static HashSet<String> blacklist = null;
+    private static HashSet<String> blacklist = null;
+
+    public static boolean isBlacklisted(String packageName) {
+        return blacklist != null && blacklist.contains(packageName);
+    }
+
+    public static void setBlackList(Set<String> packageNames) {
+        if (packageNames == null) {
+            blacklist = new HashSet<>();
+        } else {
+            blacklist = new HashSet<>(packageNames);
+        }
+        saveBlackList();
+    }
 
     private static void loadBlackList() {
-        blacklist = (HashSet<String>) sharedPrefs.getStringSet("package_blacklist", null);
+        blacklist = (HashSet<String>) sharedPrefs.getStringSet(GBPrefs.PACKAGE_BLACKLIST, null);
         if (blacklist == null) {
             blacklist = new HashSet<>();
         }
@@ -325,16 +339,15 @@ public class GBApplication extends Application {
     private static void saveBlackList() {
         SharedPreferences.Editor editor = sharedPrefs.edit();
         if (blacklist.isEmpty()) {
-            editor.putStringSet("package_blacklist", null);
+            editor.putStringSet(GBPrefs.PACKAGE_BLACKLIST, null);
         } else {
-            editor.putStringSet("package_blacklist", blacklist);
+            editor.putStringSet(GBPrefs.PACKAGE_BLACKLIST, blacklist);
         }
         editor.apply();
     }
 
     public static void addToBlacklist(String packageName) {
-        if (!blacklist.contains(packageName)) {
-            blacklist.add(packageName);
+        if (blacklist.add(packageName)) {
             saveBlackList();
         }
     }
diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/activities/AppBlacklistActivity.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/activities/AppBlacklistActivity.java
index cb975442..fb49fee7 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/activities/AppBlacklistActivity.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/activities/AppBlacklistActivity.java
@@ -21,7 +21,6 @@ import android.content.BroadcastReceiver;
 import android.content.Context;
 import android.content.Intent;
 import android.content.IntentFilter;
-import android.content.pm.ApplicationInfo;
 import android.os.Bundle;
 import android.support.v4.app.NavUtils;
 import android.support.v4.content.LocalBroadcastManager;
@@ -33,8 +32,6 @@ import android.view.MenuItem;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
-import java.util.IdentityHashMap;
-
 import nodomain.freeyourgadget.gadgetbridge.GBApplication;
 import nodomain.freeyourgadget.gadgetbridge.R;
 import nodomain.freeyourgadget.gadgetbridge.adapter.AppBlacklistAdapter;
@@ -55,8 +52,6 @@ public class AppBlacklistActivity extends GBActivity {
         }
     };
 
-    private IdentityHashMap<ApplicationInfo, String> nameMap;
-
     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/adapter/AppBlacklistAdapter.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/adapter/AppBlacklistAdapter.java
index b2b2a3c1..a99ae628 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/adapter/AppBlacklistAdapter.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/adapter/AppBlacklistAdapter.java
@@ -40,13 +40,13 @@ public class AppBlacklistAdapter extends RecyclerView.Adapter<AppBlacklistAdapte
         applicationInfoList = mPm.getInstalledApplications(PackageManager.GET_META_DATA);
 
         // sort the package list by label and blacklist status
-        mNameMap = new IdentityHashMap<ApplicationInfo, String>(applicationInfoList.size());
+        mNameMap = new IdentityHashMap<>(applicationInfoList.size());
         for (ApplicationInfo ai : applicationInfoList) {
             CharSequence name = mPm.getApplicationLabel(ai);
             if (name == null) {
                 name = ai.packageName;
             }
-            if (GBApplication.blacklist.contains(ai.packageName)) {
+            if (GBApplication.isBlacklisted(ai.packageName)) {
                 // sort blacklisted first by prefixing with a '!'
                 name = "!" + name;
             }
@@ -78,7 +78,7 @@ public class AppBlacklistAdapter extends RecyclerView.Adapter<AppBlacklistAdapte
         holder.deviceAppNameLabel.setText(mNameMap.get(appInfo));
         holder.deviceImageView.setImageDrawable(appInfo.loadIcon(mPm));
 
-        holder.checkbox.setChecked(GBApplication.blacklist.contains(appInfo.packageName));
+        holder.checkbox.setChecked(GBApplication.isBlacklisted(appInfo.packageName));
 
         holder.itemView.setOnClickListener(new View.OnClickListener() {
             @Override
diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/externalevents/NotificationListener.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/externalevents/NotificationListener.java
index 62b06d0c..0b32ba7e 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/externalevents/NotificationListener.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/externalevents/NotificationListener.java
@@ -242,7 +242,7 @@ public class NotificationListener extends NotificationListenerService {
             }
         }
 
-        if (GBApplication.blacklist != null && GBApplication.blacklist.contains(source)) {
+        if (GBApplication.isBlacklisted(source)) {
             LOG.info("Not forwarding notification, application is blacklisted");
             return;
         }
diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/util/GBPrefs.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/util/GBPrefs.java
index a59a1ab1..763251b9 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/util/GBPrefs.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/util/GBPrefs.java
@@ -20,7 +20,7 @@ import java.text.ParseException;
 import java.util.Date;
 
 public class GBPrefs {
-
+    public static final String PACKAGE_BLACKLIST = "package_blacklist";
     public static final String AUTO_RECONNECT = "general_autocreconnect";
     private static final String AUTO_START = "general_autostartonboot";
     private static final boolean AUTO_START_DEFAULT = true;
@@ -61,7 +61,7 @@ public class GBPrefs {
         }
     }
 
-    public int getUserSex() {
+    public int getUserGender() {
         return 0;
     }
 }
diff --git a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/util/ImportExportSharedPreferences.java b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/util/ImportExportSharedPreferences.java
index b51fdecf..cf0bc13e 100644
--- a/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/util/ImportExportSharedPreferences.java
+++ b/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/util/ImportExportSharedPreferences.java
@@ -17,7 +17,7 @@ import org.xmlpull.v1.XmlSerializer;
 import android.content.SharedPreferences;
 import android.util.Xml;
 
-import static nodomain.freeyourgadget.gadgetbridge.GBApplication.blacklist;
+import nodomain.freeyourgadget.gadgetbridge.GBApplication;
 
 public class ImportExportSharedPreferences {
 
@@ -26,7 +26,7 @@ public class ImportExportSharedPreferences {
     private static final String INTEGER = Integer.class.getSimpleName();
     private static final String LONG = Long.class.getSimpleName();
     private static final String STRING = String.class.getSimpleName();
-    private static final String HASTSET = HashSet.class.getSimpleName();
+    private static final String HASHSET = HashSet.class.getSimpleName();
 
     private static final String NAME = "name";
     private static final String PREFERENCES = "preferences";
@@ -107,14 +107,14 @@ public class ImportExportSharedPreferences {
                         editor.putLong(key, Long.parseLong(text));
                     } else if (STRING.equals(name)) {
                         editor.putString(key, text);
-                    } else if (HASTSET.equals(name)) {
-                        if (key.equals("package_blacklist")) {
-                            blacklist.clear();
+                    } else if (HASHSET.equals(name)) {
+                        if (key.equals(GBPrefs.PACKAGE_BLACKLIST)) {
+                            Set<String> blacklist = new HashSet<>();
                             text=text.replace("[","").replace("]","");
                             for (int z=0;z<text.split(",").length;z++){
                                 blacklist.add(text.split(",")[z].trim());
                             }
-                            editor.putStringSet(key, blacklist);
+                            GBApplication.setBlackList(blacklist);
                         }
                     } else if (!PREFERENCES.equals(name)) {
                         throw new Exception("Unkown type " + name);