diff --git a/app/src/main/java/org/fdroid/fdroid/ProgressBufferedInputStream.java b/app/src/main/java/org/fdroid/fdroid/ProgressBufferedInputStream.java
index e849fe3cb..1340877fd 100644
--- a/app/src/main/java/org/fdroid/fdroid/ProgressBufferedInputStream.java
+++ b/app/src/main/java/org/fdroid/fdroid/ProgressBufferedInputStream.java
@@ -1,5 +1,7 @@
 package org.fdroid.fdroid;
 
+import android.support.annotation.NonNull;
+
 import java.io.BufferedInputStream;
 import java.io.IOException;
 import java.io.InputStream;
@@ -24,7 +26,7 @@ class ProgressBufferedInputStream extends BufferedInputStream {
     }
 
     @Override
-    public int read(byte[] buffer, int byteOffset, int byteCount) throws IOException {
+    public int read(@NonNull byte[] buffer, int byteOffset, int byteCount) throws IOException {
         if (progressListener != null) {
             currentBytes += byteCount;
             /* don't send every change to keep things efficient.  333333 bytes to keep all
diff --git a/app/src/main/java/org/fdroid/fdroid/data/ApkProvider.java b/app/src/main/java/org/fdroid/fdroid/data/ApkProvider.java
index 3a1ea2cf1..620096aad 100644
--- a/app/src/main/java/org/fdroid/fdroid/data/ApkProvider.java
+++ b/app/src/main/java/org/fdroid/fdroid/data/ApkProvider.java
@@ -485,7 +485,8 @@ public class ApkProvider extends FDroidProvider {
     }
 
     @Override
-    public Cursor query(Uri uri, String[] projection, String selection, String[] selectionArgs, String sortOrder) {
+    public Cursor query(@NonNull Uri uri, String[] projection, String selection,
+                        String[] selectionArgs, String sortOrder) {
 
         QuerySelection query = new QuerySelection(selection, selectionArgs);
 
@@ -554,7 +555,7 @@ public class ApkProvider extends FDroidProvider {
     }
 
     @Override
-    public Uri insert(Uri uri, ContentValues values) {
+    public Uri insert(@NonNull Uri uri, ContentValues values) {
         boolean saveAntiFeatures = false;
         String[] antiFeatures = null;
         if (values.containsKey(Cols.AntiFeatures.ANTI_FEATURES)) {
@@ -626,7 +627,7 @@ public class ApkProvider extends FDroidProvider {
     }
 
     @Override
-    public int delete(Uri uri, String where, String[] whereArgs) {
+    public int delete(@NonNull Uri uri, String where, String[] whereArgs) {
 
         QuerySelection query = new QuerySelection(where, whereArgs);
 
@@ -652,7 +653,7 @@ public class ApkProvider extends FDroidProvider {
     }
 
     @Override
-    public int update(Uri uri, ContentValues values, String where, String[] whereArgs) {
+    public int update(@NonNull Uri uri, ContentValues values, String where, String[] whereArgs) {
         if (MATCHER.match(uri) != CODE_APK_FROM_REPO) {
             throw new UnsupportedOperationException("Cannot update anything other than a single apk.");
         }
diff --git a/app/src/main/java/org/fdroid/fdroid/data/TempApkProvider.java b/app/src/main/java/org/fdroid/fdroid/data/TempApkProvider.java
index 3c00ea546..1fb532f6a 100644
--- a/app/src/main/java/org/fdroid/fdroid/data/TempApkProvider.java
+++ b/app/src/main/java/org/fdroid/fdroid/data/TempApkProvider.java
@@ -5,6 +5,7 @@ import android.content.Context;
 import android.content.UriMatcher;
 import android.database.sqlite.SQLiteDatabase;
 import android.net.Uri;
+import android.support.annotation.NonNull;
 
 import org.fdroid.fdroid.data.Schema.ApkTable;
 import org.fdroid.fdroid.data.Schema.ApkTable.Cols;
@@ -75,7 +76,7 @@ public class TempApkProvider extends ApkProvider {
     }
 
     @Override
-    public Uri insert(Uri uri, ContentValues values) {
+    public Uri insert(@NonNull Uri uri, ContentValues values) {
         if (MATCHER.match(uri) == CODE_INIT) {
             initTable(Long.parseLong(uri.getLastPathSegment()));
             return null;
@@ -85,12 +86,12 @@ public class TempApkProvider extends ApkProvider {
     }
 
     @Override
-    public int update(Uri uri, ContentValues values, String where, String[] whereArgs) {
+    public int update(@NonNull Uri uri, ContentValues values, String where, String[] whereArgs) {
         throw new UnsupportedOperationException("Invalid URI for apk content provider: " + uri);
     }
 
     @Override
-    public int delete(Uri uri, String where, String[] whereArgs) {
+    public int delete(@NonNull Uri uri, String where, String[] whereArgs) {
         throw new UnsupportedOperationException("Invalid URI for apk content provider: " + uri);
     }
 
diff --git a/app/src/main/java/org/fdroid/fdroid/data/TempAppProvider.java b/app/src/main/java/org/fdroid/fdroid/data/TempAppProvider.java
index 0f37a4fb9..12bb497e0 100644
--- a/app/src/main/java/org/fdroid/fdroid/data/TempAppProvider.java
+++ b/app/src/main/java/org/fdroid/fdroid/data/TempAppProvider.java
@@ -7,6 +7,7 @@ import android.database.Cursor;
 import android.database.sqlite.SQLiteDatabase;
 import android.database.sqlite.SQLiteException;
 import android.net.Uri;
+import android.support.annotation.NonNull;
 import android.text.TextUtils;
 import org.fdroid.fdroid.data.Schema.ApkTable;
 import org.fdroid.fdroid.data.Schema.AppMetadataTable;
@@ -131,7 +132,7 @@ public class TempAppProvider extends AppProvider {
     }
 
     @Override
-    public Uri insert(Uri uri, ContentValues values) {
+    public Uri insert(@NonNull Uri uri, ContentValues values) {
         switch (MATCHER.match(uri)) {
             case CODE_INIT:
                 initTable(Long.parseLong(uri.getLastPathSegment()));
@@ -146,12 +147,12 @@ public class TempAppProvider extends AppProvider {
     }
 
     @Override
-    public int update(Uri uri, ContentValues values, String where, String[] whereArgs) {
+    public int update(@NonNull Uri uri, ContentValues values, String where, String[] whereArgs) {
         throw new UnsupportedOperationException("Update not supported for " + uri + ".");
     }
 
     @Override
-    public Cursor query(Uri uri, String[] projection,
+    public Cursor query(@NonNull Uri uri, String[] projection,
                         String customSelection, String[] selectionArgs, String sortOrder) {
         AppQuerySelection selection = new AppQuerySelection(customSelection, selectionArgs);
         switch (MATCHER.match(uri)) {
diff --git a/app/src/main/java/org/fdroid/fdroid/installer/FileInstallerActivity.java b/app/src/main/java/org/fdroid/fdroid/installer/FileInstallerActivity.java
index d610c4371..9bc3db7b8 100644
--- a/app/src/main/java/org/fdroid/fdroid/installer/FileInstallerActivity.java
+++ b/app/src/main/java/org/fdroid/fdroid/installer/FileInstallerActivity.java
@@ -6,6 +6,7 @@ import android.content.Intent;
 import android.content.pm.PackageManager;
 import android.net.Uri;
 import android.os.Bundle;
+import android.support.annotation.NonNull;
 import android.support.v4.app.ActivityCompat;
 import android.support.v4.app.FragmentActivity;
 import android.support.v4.content.ContextCompat;
@@ -121,7 +122,7 @@ public class FileInstallerActivity extends FragmentActivity {
 
     @Override
     public void onRequestPermissionsResult(int requestCode,
-                                           String[] permissions, int[] grantResults) {
+                                           @NonNull String[] permissions, @NonNull int[] grantResults) {
         switch (requestCode) {
             case MY_PERMISSIONS_REQUEST_STORAGE:
                 // If request is cancelled, the result arrays are empty.
diff --git a/app/src/main/java/org/fdroid/fdroid/net/Downloader.java b/app/src/main/java/org/fdroid/fdroid/net/Downloader.java
index 3dcb80479..2175344dd 100644
--- a/app/src/main/java/org/fdroid/fdroid/net/Downloader.java
+++ b/app/src/main/java/org/fdroid/fdroid/net/Downloader.java
@@ -1,6 +1,8 @@
 package org.fdroid.fdroid.net;
 
 import android.net.Uri;
+import android.support.annotation.NonNull;
+
 import org.fdroid.fdroid.ProgressListener;
 import org.fdroid.fdroid.Utils;
 
@@ -243,12 +245,12 @@ public abstract class Downloader {
         }
 
         @Override
-        public int read(byte[] buffer) throws IOException {
+        public int read(@NonNull byte[] buffer) throws IOException {
             return toWrap.read(buffer);
         }
 
         @Override
-        public int read(byte[] buffer, int byteOffset, int byteCount) throws IOException {
+        public int read(@NonNull byte[] buffer, int byteOffset, int byteCount) throws IOException {
             return toWrap.read(buffer, byteOffset, byteCount);
         }
 
diff --git a/app/src/main/java/org/fdroid/fdroid/net/HttpDownloader.java b/app/src/main/java/org/fdroid/fdroid/net/HttpDownloader.java
index 87ba6a81d..eab3097f1 100644
--- a/app/src/main/java/org/fdroid/fdroid/net/HttpDownloader.java
+++ b/app/src/main/java/org/fdroid/fdroid/net/HttpDownloader.java
@@ -78,7 +78,6 @@ public class HttpDownloader extends Downloader {
      * @param destFile Where the download is saved
      * @param username Username for HTTP Basic Auth, use {@code null} to ignore
      * @param password Password for HTTP Basic Auth, use {@code null} to ignore
-     * @throws FileNotFoundException
      * @throws MalformedURLException
      */
     HttpDownloader(Uri uri, File destFile, String username, String password)
diff --git a/app/src/main/java/org/fdroid/fdroid/privileged/views/TabsAdapter.java b/app/src/main/java/org/fdroid/fdroid/privileged/views/TabsAdapter.java
index 2714524e6..7c03dbe2c 100644
--- a/app/src/main/java/org/fdroid/fdroid/privileged/views/TabsAdapter.java
+++ b/app/src/main/java/org/fdroid/fdroid/privileged/views/TabsAdapter.java
@@ -20,6 +20,7 @@ package org.fdroid.fdroid.privileged.views;
 import android.app.Activity;
 import android.content.Context;
 import android.graphics.Rect;
+import android.support.annotation.NonNull;
 import android.support.v4.view.PagerAdapter;
 import android.support.v4.view.ViewPager;
 import android.view.View;
@@ -87,20 +88,21 @@ class TabsAdapter extends PagerAdapter
         return tabs.size();
     }
 
+    @NonNull
     @Override
-    public Object instantiateItem(ViewGroup container, int position) {
+    public Object instantiateItem(@NonNull ViewGroup container, int position) {
         View view = tabs.get(position);
         container.addView(view);
         return view;
     }
 
     @Override
-    public void destroyItem(ViewGroup container, int position, Object object) {
+    public void destroyItem(@NonNull ViewGroup container, int position, @NonNull Object object) {
         container.removeView((View) object);
     }
 
     @Override
-    public boolean isViewFromObject(View view, Object object) {
+    public boolean isViewFromObject(@NonNull View view, @NonNull Object object) {
         return view == object;
     }
 
diff --git a/app/src/main/java/org/fdroid/fdroid/receiver/PackageManagerReceiver.java b/app/src/main/java/org/fdroid/fdroid/receiver/PackageManagerReceiver.java
index be53cbd87..bfa16480b 100644
--- a/app/src/main/java/org/fdroid/fdroid/receiver/PackageManagerReceiver.java
+++ b/app/src/main/java/org/fdroid/fdroid/receiver/PackageManagerReceiver.java
@@ -14,7 +14,7 @@ import org.fdroid.fdroid.data.InstalledAppProviderService;
  * {@link Intent#EXTRA_REPLACING} and instead handles updates by just deleting then
  * inserting the app being updated in direct response to the {@code Intent}s from
  * the system.  This is also necessary because there are no other checks to prevent
- * multiple copies of the same app being inserted into {@Link InstalledAppProvider}.
+ * multiple copies of the same app being inserted into {@link InstalledAppProviderService}.
  */
 public class PackageManagerReceiver extends BroadcastReceiver {
     private static final String TAG = "PackageManagerReceiver";
diff --git a/app/src/main/java/org/fdroid/fdroid/views/AppDetailsRecyclerViewAdapter.java b/app/src/main/java/org/fdroid/fdroid/views/AppDetailsRecyclerViewAdapter.java
index 49b714f30..485a67f81 100644
--- a/app/src/main/java/org/fdroid/fdroid/views/AppDetailsRecyclerViewAdapter.java
+++ b/app/src/main/java/org/fdroid/fdroid/views/AppDetailsRecyclerViewAdapter.java
@@ -268,8 +268,9 @@ public class AppDetailsRecyclerViewAdapter
         }
     }
 
+    @NonNull
     @Override
-    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
+    public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
         LayoutInflater inflater = LayoutInflater.from(parent.getContext());
         switch (viewType) {
             case VIEWTYPE_HEADER:
@@ -302,7 +303,7 @@ public class AppDetailsRecyclerViewAdapter
     }
 
     @Override
-    public void onBindViewHolder(final RecyclerView.ViewHolder holder, int position) {
+    public void onBindViewHolder(@NonNull final RecyclerView.ViewHolder holder, int position) {
         int viewType = getItemViewType(position);
         switch (viewType) {
             case VIEWTYPE_HEADER:
@@ -328,7 +329,7 @@ public class AppDetailsRecyclerViewAdapter
     }
 
     @Override
-    public void onViewRecycled(RecyclerView.ViewHolder holder) {
+    public void onViewRecycled(@NonNull RecyclerView.ViewHolder holder) {
         if (holder instanceof HeaderViewHolder) {
             headerView = null;
         }
@@ -660,13 +661,13 @@ public class AppDetailsRecyclerViewAdapter
     }
 
     @Override
-    public void onAttachedToRecyclerView(RecyclerView recyclerView) {
+    public void onAttachedToRecyclerView(@NonNull RecyclerView recyclerView) {
         super.onAttachedToRecyclerView(recyclerView);
         this.recyclerView = recyclerView;
     }
 
     @Override
-    public void onDetachedFromRecyclerView(RecyclerView recyclerView) {
+    public void onDetachedFromRecyclerView(@NonNull RecyclerView recyclerView) {
         this.recyclerView = null;
         super.onDetachedFromRecyclerView(recyclerView);
     }
diff --git a/app/src/main/java/org/fdroid/fdroid/views/ManageReposActivity.java b/app/src/main/java/org/fdroid/fdroid/views/ManageReposActivity.java
index 85b30525a..57ebf4b62 100644
--- a/app/src/main/java/org/fdroid/fdroid/views/ManageReposActivity.java
+++ b/app/src/main/java/org/fdroid/fdroid/views/ManageReposActivity.java
@@ -858,6 +858,7 @@ public class ManageReposActivity extends AppCompatActivity
 
     private RepoAdapter repoAdapter;
 
+    @NonNull
     @Override
     public Loader<Cursor> onCreateLoader(int i, Bundle bundle) {
         Uri uri = RepoProvider.allExceptSwapUri();
@@ -872,12 +873,12 @@ public class ManageReposActivity extends AppCompatActivity
     }
 
     @Override
-    public void onLoadFinished(Loader<Cursor> cursorLoader, Cursor cursor) {
+    public void onLoadFinished(@NonNull Loader<Cursor> cursorLoader, Cursor cursor) {
         repoAdapter.swapCursor(cursor);
     }
 
     @Override
-    public void onLoaderReset(Loader<Cursor> cursorLoader) {
+    public void onLoaderReset(@NonNull Loader<Cursor> cursorLoader) {
         repoAdapter.swapCursor(null);
     }
 
diff --git a/app/src/main/java/org/fdroid/fdroid/views/ScreenShotsActivity.java b/app/src/main/java/org/fdroid/fdroid/views/ScreenShotsActivity.java
index 9fbb8c28a..32f043208 100644
--- a/app/src/main/java/org/fdroid/fdroid/views/ScreenShotsActivity.java
+++ b/app/src/main/java/org/fdroid/fdroid/views/ScreenShotsActivity.java
@@ -4,6 +4,7 @@ import android.annotation.TargetApi;
 import android.content.Context;
 import android.content.Intent;
 import android.os.Bundle;
+import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
 import android.support.v4.app.Fragment;
 import android.support.v4.app.FragmentManager;
@@ -125,7 +126,7 @@ public class ScreenShotsActivity extends AppCompatActivity {
 
         @Nullable
         @Override
-        public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container,
+        public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container,
                                  @Nullable Bundle savedInstanceState) {
 
             DisplayImageOptions displayImageOptions = Utils.getDefaultDisplayImageOptionsBuilder()
@@ -146,7 +147,7 @@ public class ScreenShotsActivity extends AppCompatActivity {
     @TargetApi(11)
     public static class DepthPageTransformer implements ViewPager.PageTransformer {
 
-        public void transformPage(View view, float position) {
+        public void transformPage(@NonNull View view, float position) {
             int pageWidth = view.getWidth();
 
             if (position <= 0) {
diff --git a/app/src/main/java/org/fdroid/fdroid/views/ScreenShotsRecyclerViewAdapter.java b/app/src/main/java/org/fdroid/fdroid/views/ScreenShotsRecyclerViewAdapter.java
index d6530e961..d77bdc2df 100644
--- a/app/src/main/java/org/fdroid/fdroid/views/ScreenShotsRecyclerViewAdapter.java
+++ b/app/src/main/java/org/fdroid/fdroid/views/ScreenShotsRecyclerViewAdapter.java
@@ -1,6 +1,7 @@
 package org.fdroid.fdroid.views;
 
 import android.content.Context;
+import android.support.annotation.NonNull;
 import android.support.v7.widget.RecyclerView;
 import android.view.LayoutInflater;
 import android.view.View;
@@ -33,14 +34,15 @@ class ScreenShotsRecyclerViewAdapter extends RecyclerView.Adapter<RecyclerView.V
     }
 
     @Override
-    public void onBindViewHolder(RecyclerView.ViewHolder holder, final int position) {
+    public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, final int position) {
         final ScreenShotViewHolder vh = (ScreenShotViewHolder) holder;
         ImageLoader.getInstance().displayImage(screenshots[position],
                 vh.image, displayImageOptions);
     }
 
+    @NonNull
     @Override
-    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
+    public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
         View view = LayoutInflater.from(parent.getContext())
                 .inflate(R.layout.app_details2_screenshot_item, parent, false);
         return new ScreenShotViewHolder(view);
diff --git a/app/src/main/java/org/fdroid/fdroid/views/ShareChooserDialog.java b/app/src/main/java/org/fdroid/fdroid/views/ShareChooserDialog.java
index 5310f00dd..86ca7e2a9 100644
--- a/app/src/main/java/org/fdroid/fdroid/views/ShareChooserDialog.java
+++ b/app/src/main/java/org/fdroid/fdroid/views/ShareChooserDialog.java
@@ -90,7 +90,7 @@ public class ShareChooserDialog extends BottomSheetDialogFragment {
     }
 
     @Override
-    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
+    public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
         View v = inflater.inflate(R.layout.share_chooser, container, false);
         setupView(v);
         return v;
@@ -153,8 +153,9 @@ public class ShareChooserDialog extends BottomSheetDialogFragment {
                 return VIEWTYPE_INTENT;
             }
 
+            @NonNull
             @Override
-            public VH onCreateViewHolder(ViewGroup parent, int viewType) {
+            public VH onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
                 View view = LayoutInflater.from(parent.getContext()).inflate((viewType == 1)
                         ? R.layout.share_header_item
                         : R.layout.share_item, parent, false);
@@ -162,7 +163,7 @@ public class ShareChooserDialog extends BottomSheetDialogFragment {
             }
 
             @Override
-            public void onBindViewHolder(VH holder, int position) {
+            public void onBindViewHolder(@NonNull VH holder, int position) {
                 if (getItemViewType(position) == VIEWTYPE_SWAP) {
                     holder.itemView.setOnClickListener(new View.OnClickListener() {
                         @Override
diff --git a/app/src/main/java/org/fdroid/fdroid/views/apps/AppListActivity.java b/app/src/main/java/org/fdroid/fdroid/views/apps/AppListActivity.java
index 3f3410f1f..2ba51cdf1 100644
--- a/app/src/main/java/org/fdroid/fdroid/views/apps/AppListActivity.java
+++ b/app/src/main/java/org/fdroid/fdroid/views/apps/AppListActivity.java
@@ -178,6 +178,7 @@ public class AppListActivity extends AppCompatActivity implements LoaderManager.
         return string.toString();
     }
 
+    @NonNull
     @Override
     public Loader<Cursor> onCreateLoader(int id, Bundle args) {
         return new CursorLoader(
@@ -191,7 +192,7 @@ public class AppListActivity extends AppCompatActivity implements LoaderManager.
     }
 
     @Override
-    public void onLoadFinished(Loader<Cursor> loader, Cursor cursor) {
+    public void onLoadFinished(@NonNull Loader<Cursor> loader, Cursor cursor) {
         appAdapter.setAppCursor(cursor);
         if (cursor.getCount() > 0) {
             emptyState.setVisibility(View.GONE);
@@ -203,7 +204,7 @@ public class AppListActivity extends AppCompatActivity implements LoaderManager.
     }
 
     @Override
-    public void onLoaderReset(Loader<Cursor> loader) {
+    public void onLoaderReset(@NonNull Loader<Cursor> loader) {
         appAdapter.setAppCursor(null);
     }
 
diff --git a/app/src/main/java/org/fdroid/fdroid/views/apps/AppListAdapter.java b/app/src/main/java/org/fdroid/fdroid/views/apps/AppListAdapter.java
index 32fc0561d..0b7762f53 100644
--- a/app/src/main/java/org/fdroid/fdroid/views/apps/AppListAdapter.java
+++ b/app/src/main/java/org/fdroid/fdroid/views/apps/AppListAdapter.java
@@ -2,6 +2,7 @@ package org.fdroid.fdroid.views.apps;
 
 import android.app.Activity;
 import android.database.Cursor;
+import android.support.annotation.NonNull;
 import android.support.v7.widget.RecyclerView;
 import android.view.ViewGroup;
 import org.fdroid.fdroid.R;
@@ -25,14 +26,15 @@ class AppListAdapter extends RecyclerView.Adapter<StandardAppListItemController>
         notifyDataSetChanged();
     }
 
+    @NonNull
     @Override
-    public StandardAppListItemController onCreateViewHolder(ViewGroup parent, int viewType) {
+    public StandardAppListItemController onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
         return new StandardAppListItemController(activity, activity.getLayoutInflater()
                 .inflate(R.layout.app_list_item, parent, false));
     }
 
     @Override
-    public void onBindViewHolder(StandardAppListItemController holder, int position) {
+    public void onBindViewHolder(@NonNull StandardAppListItemController holder, int position) {
         cursor.moveToPosition(position);
         final App app = new App(cursor);
         holder.bindModel(app);
@@ -50,13 +52,13 @@ class AppListAdapter extends RecyclerView.Adapter<StandardAppListItemController>
     }
 
     @Override
-    public void onAttachedToRecyclerView(RecyclerView recyclerView) {
+    public void onAttachedToRecyclerView(@NonNull RecyclerView recyclerView) {
         super.onAttachedToRecyclerView(recyclerView);
         recyclerView.addItemDecoration(divider);
     }
 
     @Override
-    public void onDetachedFromRecyclerView(RecyclerView recyclerView) {
+    public void onDetachedFromRecyclerView(@NonNull RecyclerView recyclerView) {
         recyclerView.removeItemDecoration(divider);
         super.onDetachedFromRecyclerView(recyclerView);
     }
diff --git a/app/src/main/java/org/fdroid/fdroid/views/apps/FeatureImage.java b/app/src/main/java/org/fdroid/fdroid/views/apps/FeatureImage.java
index 20555f685..238c07026 100644
--- a/app/src/main/java/org/fdroid/fdroid/views/apps/FeatureImage.java
+++ b/app/src/main/java/org/fdroid/fdroid/views/apps/FeatureImage.java
@@ -261,7 +261,7 @@ public class FeatureImage extends AppCompatImageView {
                 if (loadedImage != null) {
                     new Palette.Builder(loadedImage).generate(new Palette.PaletteAsyncListener() {
                         @Override
-                        public void onGenerated(Palette palette) {
+                        public void onGenerated(@NonNull Palette palette) {
                             if (palette != null) {
                                 setColorAndAnimateChange(palette.getDominantColor(Color.LTGRAY));
                             }
diff --git a/app/src/main/java/org/fdroid/fdroid/views/categories/AppCardController.java b/app/src/main/java/org/fdroid/fdroid/views/categories/AppCardController.java
index 914285220..fb72a3537 100644
--- a/app/src/main/java/org/fdroid/fdroid/views/categories/AppCardController.java
+++ b/app/src/main/java/org/fdroid/fdroid/views/categories/AppCardController.java
@@ -184,7 +184,7 @@ public class AppCardController extends RecyclerView.ViewHolder
                 && loadedImage != null) {
             new Palette.Builder(loadedImage).generate(new Palette.PaletteAsyncListener() {
                 @Override
-                public void onGenerated(Palette palette) {
+                public void onGenerated(@NonNull Palette palette) {
                     featuredImage.setColorAndAnimateChange(palette.getDominantColor(Color.LTGRAY));
                 }
             });
diff --git a/app/src/main/java/org/fdroid/fdroid/views/categories/AppPreviewAdapter.java b/app/src/main/java/org/fdroid/fdroid/views/categories/AppPreviewAdapter.java
index e0eeb5b79..10388e305 100644
--- a/app/src/main/java/org/fdroid/fdroid/views/categories/AppPreviewAdapter.java
+++ b/app/src/main/java/org/fdroid/fdroid/views/categories/AppPreviewAdapter.java
@@ -2,6 +2,7 @@ package org.fdroid.fdroid.views.categories;
 
 import android.app.Activity;
 import android.database.Cursor;
+import android.support.annotation.NonNull;
 import android.support.v7.widget.RecyclerView;
 import android.view.ViewGroup;
 import org.fdroid.fdroid.R;
@@ -16,14 +17,15 @@ class AppPreviewAdapter extends RecyclerView.Adapter<AppCardController> {
         this.activity = activity;
     }
 
+    @NonNull
     @Override
-    public AppCardController onCreateViewHolder(ViewGroup parent, int viewType) {
+    public AppCardController onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
         return new AppCardController(activity, activity.getLayoutInflater()
                 .inflate(R.layout.app_card_normal, parent, false));
     }
 
     @Override
-    public void onBindViewHolder(AppCardController holder, int position) {
+    public void onBindViewHolder(@NonNull AppCardController holder, int position) {
         cursor.moveToPosition(position);
         holder.bindApp(new App(cursor));
     }
diff --git a/app/src/main/java/org/fdroid/fdroid/views/categories/CategoryAdapter.java b/app/src/main/java/org/fdroid/fdroid/views/categories/CategoryAdapter.java
index 055546dd5..e8aa99449 100644
--- a/app/src/main/java/org/fdroid/fdroid/views/categories/CategoryAdapter.java
+++ b/app/src/main/java/org/fdroid/fdroid/views/categories/CategoryAdapter.java
@@ -23,14 +23,15 @@ public class CategoryAdapter extends RecyclerView.Adapter<CategoryController> {
         this.loaderManager = loaderManager;
     }
 
+    @NonNull
     @Override
-    public CategoryController onCreateViewHolder(ViewGroup parent, int viewType) {
+    public CategoryController onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
         return new CategoryController(activity, loaderManager, activity.getLayoutInflater()
                 .inflate(R.layout.category_item, parent, false));
     }
 
     @Override
-    public void onBindViewHolder(CategoryController holder, int position) {
+    public void onBindViewHolder(@NonNull CategoryController holder, int position) {
         holder.bindModel(unlocalizedCategoryNames.get(position));
     }
 
diff --git a/app/src/main/java/org/fdroid/fdroid/views/categories/CategoryController.java b/app/src/main/java/org/fdroid/fdroid/views/categories/CategoryController.java
index 371623c8e..0815b5b76 100644
--- a/app/src/main/java/org/fdroid/fdroid/views/categories/CategoryController.java
+++ b/app/src/main/java/org/fdroid/fdroid/views/categories/CategoryController.java
@@ -133,6 +133,7 @@ public class CategoryController extends RecyclerView.ViewHolder implements Loade
         return Color.HSVToColor(hsv);
     }
 
+    @NonNull
     @Override
     public Loader<Cursor> onCreateLoader(int id, Bundle args) {
         if (id == currentCategory.hashCode() + 1) {
@@ -162,7 +163,7 @@ public class CategoryController extends RecyclerView.ViewHolder implements Loade
     }
 
     @Override
-    public void onLoadFinished(Loader<Cursor> loader, Cursor cursor) {
+    public void onLoadFinished(@NonNull Loader<Cursor> loader, Cursor cursor) {
         int topAppsId = currentCategory.hashCode();
         int countAllAppsId = topAppsId + 1;
 
@@ -184,7 +185,7 @@ public class CategoryController extends RecyclerView.ViewHolder implements Loade
     }
 
     @Override
-    public void onLoaderReset(Loader<Cursor> loader) {
+    public void onLoaderReset(@NonNull Loader<Cursor> loader) {
         appCardsAdapter.setAppCursor(null);
     }
 
diff --git a/app/src/main/java/org/fdroid/fdroid/views/installed/InstalledAppListAdapter.java b/app/src/main/java/org/fdroid/fdroid/views/installed/InstalledAppListAdapter.java
index 438fdc3f4..0667afb96 100644
--- a/app/src/main/java/org/fdroid/fdroid/views/installed/InstalledAppListAdapter.java
+++ b/app/src/main/java/org/fdroid/fdroid/views/installed/InstalledAppListAdapter.java
@@ -2,6 +2,7 @@ package org.fdroid.fdroid.views.installed;
 
 import android.app.Activity;
 import android.database.Cursor;
+import android.support.annotation.NonNull;
 import android.support.annotation.Nullable;
 import android.support.v7.widget.RecyclerView;
 import android.view.View;
@@ -32,14 +33,15 @@ class InstalledAppListAdapter extends RecyclerView.Adapter<InstalledAppListItemC
         return cursor.getLong(cursor.getColumnIndex(Schema.AppMetadataTable.Cols.ROW_ID));
     }
 
+    @NonNull
     @Override
-    public InstalledAppListItemController onCreateViewHolder(ViewGroup parent, int viewType) {
+    public InstalledAppListItemController onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
         View view = activity.getLayoutInflater().inflate(R.layout.installed_app_list_item, parent, false);
         return new InstalledAppListItemController(activity, view);
     }
 
     @Override
-    public void onBindViewHolder(InstalledAppListItemController holder, int position) {
+    public void onBindViewHolder(@NonNull InstalledAppListItemController holder, int position) {
         if (cursor == null) {
             return;
         }
diff --git a/app/src/main/java/org/fdroid/fdroid/views/installed/InstalledAppsActivity.java b/app/src/main/java/org/fdroid/fdroid/views/installed/InstalledAppsActivity.java
index 9020af3a9..cfb293241 100644
--- a/app/src/main/java/org/fdroid/fdroid/views/installed/InstalledAppsActivity.java
+++ b/app/src/main/java/org/fdroid/fdroid/views/installed/InstalledAppsActivity.java
@@ -21,6 +21,7 @@ package org.fdroid.fdroid.views.installed;
 
 import android.database.Cursor;
 import android.os.Bundle;
+import android.support.annotation.NonNull;
 import android.support.v4.app.LoaderManager;
 import android.support.v4.app.ShareCompat;
 import android.support.v4.content.CursorLoader;
@@ -76,6 +77,7 @@ public class InstalledAppsActivity extends AppCompatActivity implements LoaderMa
         getSupportLoaderManager().restartLoader(0, null, this);
     }
 
+    @NonNull
     @Override
     public Loader<Cursor> onCreateLoader(int id, Bundle args) {
         return new CursorLoader(
@@ -86,7 +88,7 @@ public class InstalledAppsActivity extends AppCompatActivity implements LoaderMa
     }
 
     @Override
-    public void onLoadFinished(Loader<Cursor> loader, Cursor cursor) {
+    public void onLoadFinished(@NonNull Loader<Cursor> loader, Cursor cursor) {
         adapter.setApps(cursor);
 
         if (adapter.getItemCount() == 0) {
@@ -99,7 +101,7 @@ public class InstalledAppsActivity extends AppCompatActivity implements LoaderMa
     }
 
     @Override
-    public void onLoaderReset(Loader<Cursor> loader) {
+    public void onLoaderReset(@NonNull Loader<Cursor> loader) {
         adapter.setApps(null);
     }
 
diff --git a/app/src/main/java/org/fdroid/fdroid/views/main/MainViewAdapter.java b/app/src/main/java/org/fdroid/fdroid/views/main/MainViewAdapter.java
index 729fcd458..a670fd2d0 100644
--- a/app/src/main/java/org/fdroid/fdroid/views/main/MainViewAdapter.java
+++ b/app/src/main/java/org/fdroid/fdroid/views/main/MainViewAdapter.java
@@ -21,6 +21,7 @@
 
 package org.fdroid.fdroid.views.main;
 
+import android.support.annotation.NonNull;
 import android.support.v7.app.AppCompatActivity;
 import android.support.v7.widget.RecyclerView;
 import android.util.SparseIntArray;
@@ -63,7 +64,7 @@ class MainViewAdapter extends RecyclerView.Adapter<MainViewController> {
     }
 
     @Override
-    public void onViewDetachedFromWindow(MainViewController holder) {
+    public void onViewDetachedFromWindow(@NonNull MainViewController holder) {
         long viewType = getItemId(holder.getAdapterPosition());
         if (viewType == R.id.updates) {
             holder.unbindUpdates();
@@ -71,15 +72,16 @@ class MainViewAdapter extends RecyclerView.Adapter<MainViewController> {
     }
 
     @Override
-    public void onViewAttachedToWindow(MainViewController holder) {
+    public void onViewAttachedToWindow(@NonNull MainViewController holder) {
         long viewType = getItemId(holder.getAdapterPosition());
         if (viewType == R.id.updates) {
             holder.bindUpdates();
         }
     }
 
+    @NonNull
     @Override
-    public MainViewController onCreateViewHolder(ViewGroup parent, int viewType) {
+    public MainViewController onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
         MainViewController holder = createEmptyView();
         switch (viewType) {
             case R.id.whats_new:
@@ -112,7 +114,7 @@ class MainViewAdapter extends RecyclerView.Adapter<MainViewController> {
     }
 
     @Override
-    public void onBindViewHolder(MainViewController holder, int position) {
+    public void onBindViewHolder(@NonNull MainViewController holder, int position) {
         // The binding happens in onCreateViewHolder. This is because we never have more than one of
         // each type of view in this main activity. Therefore, there is no benefit to re-binding new
         // data each time we navigate back to an item, as the recycler view will just use the one we
diff --git a/app/src/main/java/org/fdroid/fdroid/views/main/WhatsNewViewBinder.java b/app/src/main/java/org/fdroid/fdroid/views/main/WhatsNewViewBinder.java
index c53932349..47da7ac2c 100644
--- a/app/src/main/java/org/fdroid/fdroid/views/main/WhatsNewViewBinder.java
+++ b/app/src/main/java/org/fdroid/fdroid/views/main/WhatsNewViewBinder.java
@@ -3,6 +3,7 @@ package org.fdroid.fdroid.views.main;
 import android.content.Intent;
 import android.database.Cursor;
 import android.os.Bundle;
+import android.support.annotation.NonNull;
 import android.support.design.widget.FloatingActionButton;
 import android.support.v4.app.LoaderManager;
 import android.support.v4.content.CursorLoader;
@@ -92,6 +93,7 @@ class WhatsNewViewBinder implements LoaderManager.LoaderCallbacks<Cursor> {
         activity.getSupportLoaderManager().initLoader(LOADER_ID, null, this);
     }
 
+    @NonNull
     @Override
     public Loader<Cursor> onCreateLoader(int id, Bundle args) {
         if (id != LOADER_ID) {
@@ -109,7 +111,7 @@ class WhatsNewViewBinder implements LoaderManager.LoaderCallbacks<Cursor> {
     }
 
     @Override
-    public void onLoadFinished(Loader<Cursor> loader, Cursor cursor) {
+    public void onLoadFinished(@NonNull Loader<Cursor> loader, Cursor cursor) {
         if (loader.getId() != LOADER_ID) {
             return;
         }
@@ -160,7 +162,7 @@ class WhatsNewViewBinder implements LoaderManager.LoaderCallbacks<Cursor> {
     }
 
     @Override
-    public void onLoaderReset(Loader<Cursor> loader) {
+    public void onLoaderReset(@NonNull Loader<Cursor> loader) {
         if (loader.getId() != LOADER_ID) {
             return;
         }
diff --git a/app/src/main/java/org/fdroid/fdroid/views/updates/UpdatesAdapter.java b/app/src/main/java/org/fdroid/fdroid/views/updates/UpdatesAdapter.java
index cf5594f65..15cf1b6d6 100644
--- a/app/src/main/java/org/fdroid/fdroid/views/updates/UpdatesAdapter.java
+++ b/app/src/main/java/org/fdroid/fdroid/views/updates/UpdatesAdapter.java
@@ -7,6 +7,7 @@ import android.content.IntentFilter;
 import android.database.Cursor;
 import android.net.Uri;
 import android.os.Bundle;
+import android.support.annotation.NonNull;
 import android.support.v4.app.LoaderManager;
 import android.support.v4.content.CursorLoader;
 import android.support.v4.content.Loader;
@@ -184,16 +185,18 @@ public class UpdatesAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder
         return delegatesManager.getItemViewType(items, position);
     }
 
+    @NonNull
     @Override
-    public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
+    public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
         return delegatesManager.onCreateViewHolder(parent, viewType);
     }
 
     @Override
-    public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {
+    public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {
         delegatesManager.onBindViewHolder(items, position, holder);
     }
 
+    @NonNull
     @Override
     public Loader<Cursor> onCreateLoader(int id, Bundle args) {
         Uri uri;
@@ -215,7 +218,7 @@ public class UpdatesAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder
     }
 
     @Override
-    public void onLoadFinished(Loader<Cursor> loader, Cursor cursor) {
+    public void onLoadFinished(@NonNull Loader<Cursor> loader, Cursor cursor) {
         switch (loader.getId()) {
             case LOADER_CAN_UPDATE:
                 onCanUpdateLoadFinished(cursor);
@@ -251,7 +254,7 @@ public class UpdatesAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder
     }
 
     @Override
-    public void onLoaderReset(Loader<Cursor> loader) {
+    public void onLoaderReset(@NonNull Loader<Cursor> loader) {
     }
 
     /**
diff --git a/app/src/main/java/org/fdroid/fdroid/views/updates/items/KnownVulnAppListItemController.java b/app/src/main/java/org/fdroid/fdroid/views/updates/items/KnownVulnAppListItemController.java
index cd06c167a..61ac64c2e 100644
--- a/app/src/main/java/org/fdroid/fdroid/views/updates/items/KnownVulnAppListItemController.java
+++ b/app/src/main/java/org/fdroid/fdroid/views/updates/items/KnownVulnAppListItemController.java
@@ -88,6 +88,7 @@ public class KnownVulnAppListItemController extends AppListItemController {
         return true;
     }
 
+    @NonNull
     @Override
     protected DismissResult onDismissApp(@NonNull App app) {
         this.ignoreVulnerableApp(app);
diff --git a/app/src/main/java/org/fdroid/fdroid/views/whatsnew/WhatsNewAdapter.java b/app/src/main/java/org/fdroid/fdroid/views/whatsnew/WhatsNewAdapter.java
index 0553335a0..cf6ee8df9 100644
--- a/app/src/main/java/org/fdroid/fdroid/views/whatsnew/WhatsNewAdapter.java
+++ b/app/src/main/java/org/fdroid/fdroid/views/whatsnew/WhatsNewAdapter.java
@@ -5,6 +5,7 @@ import android.content.Context;
 import android.content.res.Resources;
 import android.database.Cursor;
 import android.graphics.Rect;
+import android.support.annotation.NonNull;
 import android.support.v4.view.ViewCompat;
 import android.support.v7.widget.GridLayoutManager;
 import android.support.v7.widget.RecyclerView;
@@ -27,19 +28,20 @@ public class WhatsNewAdapter extends RecyclerView.Adapter<AppCardController> {
     }
 
     @Override
-    public void onAttachedToRecyclerView(RecyclerView recyclerView) {
+    public void onAttachedToRecyclerView(@NonNull RecyclerView recyclerView) {
         super.onAttachedToRecyclerView(recyclerView);
         recyclerView.addItemDecoration(appListDecorator);
     }
 
     @Override
-    public void onDetachedFromRecyclerView(RecyclerView recyclerView) {
+    public void onDetachedFromRecyclerView(@NonNull RecyclerView recyclerView) {
         recyclerView.removeItemDecoration(appListDecorator);
         super.onDetachedFromRecyclerView(recyclerView);
     }
 
+    @NonNull
     @Override
-    public AppCardController onCreateViewHolder(ViewGroup parent, int viewType) {
+    public AppCardController onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
         int layout;
         if (viewType == R.id.whats_new_feature) {
             layout = R.layout.app_card_featured;
@@ -88,7 +90,7 @@ public class WhatsNewAdapter extends RecyclerView.Adapter<AppCardController> {
     }
 
     @Override
-    public void onBindViewHolder(AppCardController holder, int position) {
+    public void onBindViewHolder(@NonNull AppCardController holder, int position) {
         cursor.moveToPosition(position);
         final App app = new App(cursor);
         holder.bindApp(app);