diff --git a/app/src/main/java/com/google/android/material/appbar/FlingBehavior.java b/app/src/main/java/com/google/android/material/appbar/FlingBehavior.java
index 743ff1ff20e..ca1bd79d2cf 100644
--- a/app/src/main/java/com/google/android/material/appbar/FlingBehavior.java
+++ b/app/src/main/java/com/google/android/material/appbar/FlingBehavior.java
@@ -63,8 +63,9 @@ public boolean onRequestChildRectangleOnScreen(
         return consumed == dy;
     }
 
-    public boolean onInterceptTouchEvent(final CoordinatorLayout parent, final AppBarLayout child,
-                                         final MotionEvent ev) {
+    public boolean onInterceptTouchEvent(@NonNull final CoordinatorLayout parent,
+                                         @NonNull final AppBarLayout child,
+                                         @NonNull final MotionEvent ev) {
         for (final Integer element : skipInterceptionOfElements) {
             final View view = child.findViewById(element);
             if (view != null) {
diff --git a/app/src/main/java/org/schabi/newpipe/fragments/list/BaseListFragment.java b/app/src/main/java/org/schabi/newpipe/fragments/list/BaseListFragment.java
index c28a41b7d47..45436ab6b1f 100644
--- a/app/src/main/java/org/schabi/newpipe/fragments/list/BaseListFragment.java
+++ b/app/src/main/java/org/schabi/newpipe/fragments/list/BaseListFragment.java
@@ -389,7 +389,8 @@ protected void showStreamDialog(final StreamInfoItem item) {
     //////////////////////////////////////////////////////////////////////////*/
 
     @Override
-    public void onCreateOptionsMenu(final Menu menu, final MenuInflater inflater) {
+    public void onCreateOptionsMenu(@NonNull final Menu menu,
+                                    @NonNull final MenuInflater inflater) {
         if (DEBUG) {
             Log.d(TAG, "onCreateOptionsMenu() called with: "
                     + "menu = [" + menu + "], inflater = [" + inflater + "]");
diff --git a/app/src/main/java/org/schabi/newpipe/fragments/list/channel/ChannelFragment.java b/app/src/main/java/org/schabi/newpipe/fragments/list/channel/ChannelFragment.java
index fe07a8dc947..bc67180214c 100644
--- a/app/src/main/java/org/schabi/newpipe/fragments/list/channel/ChannelFragment.java
+++ b/app/src/main/java/org/schabi/newpipe/fragments/list/channel/ChannelFragment.java
@@ -164,7 +164,8 @@ protected void initListeners() {
     //////////////////////////////////////////////////////////////////////////*/
 
     @Override
-    public void onCreateOptionsMenu(final Menu menu, final MenuInflater inflater) {
+    public void onCreateOptionsMenu(@NonNull final Menu menu,
+                                    @NonNull final MenuInflater inflater) {
         super.onCreateOptionsMenu(menu, inflater);
         final ActionBar supportActionBar = activity.getSupportActionBar();
         if (useAsFrontPage && supportActionBar != null) {
diff --git a/app/src/main/java/org/schabi/newpipe/fragments/list/comments/CommentsFragment.java b/app/src/main/java/org/schabi/newpipe/fragments/list/comments/CommentsFragment.java
index 35ab663a626..5d2cc4fdf3a 100644
--- a/app/src/main/java/org/schabi/newpipe/fragments/list/comments/CommentsFragment.java
+++ b/app/src/main/java/org/schabi/newpipe/fragments/list/comments/CommentsFragment.java
@@ -85,7 +85,8 @@ public void handleResult(@NonNull final CommentsInfo result) {
     public void setTitle(final String title) { }
 
     @Override
-    public void onCreateOptionsMenu(final Menu menu, final MenuInflater inflater) { }
+    public void onCreateOptionsMenu(@NonNull final Menu menu,
+                                    @NonNull final MenuInflater inflater) { }
 
     @Override
     protected boolean isGridLayout() {
diff --git a/app/src/main/java/org/schabi/newpipe/fragments/list/kiosk/KioskFragment.java b/app/src/main/java/org/schabi/newpipe/fragments/list/kiosk/KioskFragment.java
index 882bb021dc0..f37f487bf52 100644
--- a/app/src/main/java/org/schabi/newpipe/fragments/list/kiosk/KioskFragment.java
+++ b/app/src/main/java/org/schabi/newpipe/fragments/list/kiosk/KioskFragment.java
@@ -131,7 +131,8 @@ public void onResume() {
     //////////////////////////////////////////////////////////////////////////*/
 
     @Override
-    public void onCreateOptionsMenu(final Menu menu, final MenuInflater inflater) {
+    public void onCreateOptionsMenu(@NonNull final Menu menu,
+                                    @NonNull final MenuInflater inflater) {
         super.onCreateOptionsMenu(menu, inflater);
         final ActionBar supportActionBar = activity.getSupportActionBar();
         if (supportActionBar != null && useAsFrontPage) {
diff --git a/app/src/main/java/org/schabi/newpipe/fragments/list/playlist/PlaylistFragment.java b/app/src/main/java/org/schabi/newpipe/fragments/list/playlist/PlaylistFragment.java
index 938cf9d6619..de96905dbc3 100644
--- a/app/src/main/java/org/schabi/newpipe/fragments/list/playlist/PlaylistFragment.java
+++ b/app/src/main/java/org/schabi/newpipe/fragments/list/playlist/PlaylistFragment.java
@@ -181,7 +181,8 @@ protected void showStreamDialog(final StreamInfoItem item) {
     }
 
     @Override
-    public void onCreateOptionsMenu(final Menu menu, final MenuInflater inflater) {
+    public void onCreateOptionsMenu(@NonNull final Menu menu,
+                                    @NonNull final MenuInflater inflater) {
         if (DEBUG) {
             Log.d(TAG, "onCreateOptionsMenu() called with: "
                     + "menu = [" + menu + "], inflater = [" + inflater + "]");
diff --git a/app/src/main/java/org/schabi/newpipe/fragments/list/search/SearchFragment.java b/app/src/main/java/org/schabi/newpipe/fragments/list/search/SearchFragment.java
index 2810b9b7677..dbf0e24dd34 100644
--- a/app/src/main/java/org/schabi/newpipe/fragments/list/search/SearchFragment.java
+++ b/app/src/main/java/org/schabi/newpipe/fragments/list/search/SearchFragment.java
@@ -413,7 +413,8 @@ public void reloadContent() {
     //////////////////////////////////////////////////////////////////////////*/
 
     @Override
-    public void onCreateOptionsMenu(final Menu menu, final MenuInflater inflater) {
+    public void onCreateOptionsMenu(@NonNull final Menu menu,
+                                    @NonNull final MenuInflater inflater) {
         super.onCreateOptionsMenu(menu, inflater);
 
         final ActionBar supportActionBar = activity.getSupportActionBar();
diff --git a/app/src/main/java/org/schabi/newpipe/fragments/list/videos/RelatedItemsFragment.java b/app/src/main/java/org/schabi/newpipe/fragments/list/videos/RelatedItemsFragment.java
index a66b7d56974..6532417c064 100644
--- a/app/src/main/java/org/schabi/newpipe/fragments/list/videos/RelatedItemsFragment.java
+++ b/app/src/main/java/org/schabi/newpipe/fragments/list/videos/RelatedItemsFragment.java
@@ -140,7 +140,8 @@ public void setTitle(final String title) {
     }
 
     @Override
-    public void onCreateOptionsMenu(final Menu menu, final MenuInflater inflater) {
+    public void onCreateOptionsMenu(@NonNull final Menu menu,
+                                    @NonNull final MenuInflater inflater) {
     }
 
     private void setInitialData(final StreamInfo info) {
diff --git a/app/src/main/java/org/schabi/newpipe/local/BaseLocalListFragment.java b/app/src/main/java/org/schabi/newpipe/local/BaseLocalListFragment.java
index 78fb200298c..32a1d414e19 100644
--- a/app/src/main/java/org/schabi/newpipe/local/BaseLocalListFragment.java
+++ b/app/src/main/java/org/schabi/newpipe/local/BaseLocalListFragment.java
@@ -9,6 +9,7 @@
 import android.view.MenuInflater;
 import android.view.View;
 
+import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.appcompat.app.ActionBar;
 import androidx.fragment.app.Fragment;
@@ -145,7 +146,8 @@ protected void initListeners() {
     //////////////////////////////////////////////////////////////////////////*/
 
     @Override
-    public void onCreateOptionsMenu(final Menu menu, final MenuInflater inflater) {
+    public void onCreateOptionsMenu(@NonNull final Menu menu,
+                                    @NonNull final MenuInflater inflater) {
         super.onCreateOptionsMenu(menu, inflater);
         if (DEBUG) {
             Log.d(TAG, "onCreateOptionsMenu() called with: "
diff --git a/app/src/main/java/org/schabi/newpipe/local/history/StatisticsPlaylistFragment.java b/app/src/main/java/org/schabi/newpipe/local/history/StatisticsPlaylistFragment.java
index 2fe757dea02..aa871190f0f 100644
--- a/app/src/main/java/org/schabi/newpipe/local/history/StatisticsPlaylistFragment.java
+++ b/app/src/main/java/org/schabi/newpipe/local/history/StatisticsPlaylistFragment.java
@@ -111,7 +111,8 @@ public void setUserVisibleHint(final boolean isVisibleToUser) {
     }
 
     @Override
-    public void onCreateOptionsMenu(final Menu menu, final MenuInflater inflater) {
+    public void onCreateOptionsMenu(@NonNull final Menu menu,
+                                    @NonNull final MenuInflater inflater) {
         super.onCreateOptionsMenu(menu, inflater);
         inflater.inflate(R.menu.menu_history, menu);
     }
diff --git a/app/src/main/java/org/schabi/newpipe/local/playlist/LocalPlaylistFragment.java b/app/src/main/java/org/schabi/newpipe/local/playlist/LocalPlaylistFragment.java
index 768b0b86215..cefc63c0da0 100644
--- a/app/src/main/java/org/schabi/newpipe/local/playlist/LocalPlaylistFragment.java
+++ b/app/src/main/java/org/schabi/newpipe/local/playlist/LocalPlaylistFragment.java
@@ -248,7 +248,8 @@ public void onPause() {
     }
 
     @Override
-    public void onCreateOptionsMenu(final Menu menu, final MenuInflater inflater) {
+    public void onCreateOptionsMenu(@NonNull final Menu menu,
+                                    @NonNull final MenuInflater inflater) {
         if (DEBUG) {
             Log.d(TAG, "onCreateOptionsMenu() called with: "
                     + "menu = [" + menu + "], inflater = [" + inflater + "]");
diff --git a/app/src/main/java/org/schabi/newpipe/settings/PeertubeInstanceListFragment.java b/app/src/main/java/org/schabi/newpipe/settings/PeertubeInstanceListFragment.java
index 550e9be3fc4..c7cfb1f5f83 100644
--- a/app/src/main/java/org/schabi/newpipe/settings/PeertubeInstanceListFragment.java
+++ b/app/src/main/java/org/schabi/newpipe/settings/PeertubeInstanceListFragment.java
@@ -139,7 +139,8 @@ public void onDestroy() {
     //////////////////////////////////////////////////////////////////////////*/
 
     @Override
-    public void onCreateOptionsMenu(final Menu menu, final MenuInflater inflater) {
+    public void onCreateOptionsMenu(@NonNull final Menu menu,
+                                    @NonNull final MenuInflater inflater) {
         super.onCreateOptionsMenu(menu, inflater);
 
         final MenuItem restoreItem = menu
@@ -279,7 +280,7 @@ private ItemTouchHelper.SimpleCallback getItemTouchCallback() {
         return new ItemTouchHelper.SimpleCallback(ItemTouchHelper.UP | ItemTouchHelper.DOWN,
                 ItemTouchHelper.START | ItemTouchHelper.END) {
             @Override
-            public int interpolateOutOfBoundsScroll(final RecyclerView recyclerView,
+            public int interpolateOutOfBoundsScroll(@NonNull final RecyclerView recyclerView,
                                                     final int viewSize,
                                                     final int viewSizeOutOfBounds,
                                                     final int totalSize,
@@ -292,9 +293,9 @@ public int interpolateOutOfBoundsScroll(final RecyclerView recyclerView,
             }
 
             @Override
-            public boolean onMove(final RecyclerView recyclerView,
-                                  final RecyclerView.ViewHolder source,
-                                  final RecyclerView.ViewHolder target) {
+            public boolean onMove(@NonNull final RecyclerView recyclerView,
+                                  @NonNull final RecyclerView.ViewHolder source,
+                                  @NonNull final RecyclerView.ViewHolder target) {
                 if (source.getItemViewType() != target.getItemViewType()
                         || instanceListAdapter == null) {
                     return false;
@@ -317,7 +318,8 @@ public boolean isItemViewSwipeEnabled() {
             }
 
             @Override
-            public void onSwiped(final RecyclerView.ViewHolder viewHolder, final int swipeDir) {
+            public void onSwiped(@NonNull final RecyclerView.ViewHolder viewHolder,
+                                 final int swipeDir) {
                 final int position = viewHolder.getAdapterPosition();
                 // do not allow swiping the selected instance
                 if (instanceList.get(position).getUrl().equals(selectedInstance.getUrl())) {
diff --git a/app/src/main/java/org/schabi/newpipe/settings/SelectKioskFragment.java b/app/src/main/java/org/schabi/newpipe/settings/SelectKioskFragment.java
index 5c20b752ccb..9d873607614 100644
--- a/app/src/main/java/org/schabi/newpipe/settings/SelectKioskFragment.java
+++ b/app/src/main/java/org/schabi/newpipe/settings/SelectKioskFragment.java
@@ -8,6 +8,7 @@
 import android.widget.ImageView;
 import android.widget.TextView;
 
+import androidx.annotation.NonNull;
 import androidx.annotation.Nullable;
 import androidx.appcompat.content.res.AppCompatResources;
 import androidx.fragment.app.DialogFragment;
@@ -92,7 +93,7 @@ public View onCreateView(final LayoutInflater inflater, final ViewGroup containe
     //////////////////////////////////////////////////////////////////////////*/
 
     @Override
-    public void onCancel(final DialogInterface dialogInterface) {
+    public void onCancel(@NonNull final DialogInterface dialogInterface) {
         super.onCancel(dialogInterface);
         if (onCancelListener != null) {
             onCancelListener.onCancel();
@@ -138,6 +139,7 @@ public int getItemCount() {
             return kioskList.size();
         }
 
+        @NonNull
         public SelectKioskItemHolder onCreateViewHolder(final ViewGroup parent, final int type) {
             final View item = LayoutInflater.from(parent.getContext())
                     .inflate(R.layout.select_kiosk_item, parent, false);
diff --git a/app/src/main/java/org/schabi/newpipe/settings/tabs/ChooseTabsFragment.java b/app/src/main/java/org/schabi/newpipe/settings/tabs/ChooseTabsFragment.java
index 26cfda32917..6e50765ba8d 100644
--- a/app/src/main/java/org/schabi/newpipe/settings/tabs/ChooseTabsFragment.java
+++ b/app/src/main/java/org/schabi/newpipe/settings/tabs/ChooseTabsFragment.java
@@ -106,7 +106,8 @@ public void onPause() {
     //////////////////////////////////////////////////////////////////////////*/
 
     @Override
-    public void onCreateOptionsMenu(final Menu menu, final MenuInflater inflater) {
+    public void onCreateOptionsMenu(@NonNull final Menu menu,
+                                    @NonNull final MenuInflater inflater) {
         super.onCreateOptionsMenu(menu, inflater);
 
         final MenuItem restoreItem = menu.add(Menu.NONE, MENU_ITEM_RESTORE_ID, Menu.NONE,
@@ -277,7 +278,7 @@ private ItemTouchHelper.SimpleCallback getItemTouchCallback() {
         return new ItemTouchHelper.SimpleCallback(ItemTouchHelper.UP | ItemTouchHelper.DOWN,
                 ItemTouchHelper.START | ItemTouchHelper.END) {
             @Override
-            public int interpolateOutOfBoundsScroll(final RecyclerView recyclerView,
+            public int interpolateOutOfBoundsScroll(@NonNull final RecyclerView recyclerView,
                                                     final int viewSize,
                                                     final int viewSizeOutOfBounds,
                                                     final int totalSize,
@@ -290,9 +291,9 @@ public int interpolateOutOfBoundsScroll(final RecyclerView recyclerView,
             }
 
             @Override
-            public boolean onMove(final RecyclerView recyclerView,
-                                  final RecyclerView.ViewHolder source,
-                                  final RecyclerView.ViewHolder target) {
+            public boolean onMove(@NonNull final RecyclerView recyclerView,
+                                  @NonNull final RecyclerView.ViewHolder source,
+                                  @NonNull final RecyclerView.ViewHolder target) {
                 if (source.getItemViewType() != target.getItemViewType()
                         || selectedTabsAdapter == null) {
                     return false;
@@ -315,7 +316,8 @@ public boolean isItemViewSwipeEnabled() {
             }
 
             @Override
-            public void onSwiped(final RecyclerView.ViewHolder viewHolder, final int swipeDir) {
+            public void onSwiped(@NonNull final RecyclerView.ViewHolder viewHolder,
+                                 final int swipeDir) {
                 final int position = viewHolder.getAdapterPosition();
                 tabList.remove(position);
                 selectedTabsAdapter.notifyItemRemoved(position);