global: get rid of nonnull gradle hack

Hacking things up via gradle is not right, and package-info.java poses
problems with two modules, so instead we just apply it manually to every
class.

Remember to add this to new classes!

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>

46 files changed, 137 insertions, 0 deletions

diff --git a/ui/src/main/java/com/wireguard/android/Application.java b/ui/src/main/java/com/wireguard/android/Application.java
index e32c3755..d3e0aa5f 100644
--- a/ui/src/main/java/com/wireguard/android/Application.java
+++ b/ui/src/main/java/com/wireguard/android/Application.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android;
 
+import com.wireguard.util.NonNullForAll;
+
 import android.content.Context;
 import android.content.Intent;
 import android.content.SharedPreferences;
@@ -35,6 +37,7 @@ import java.util.Locale;
 
 import java9.util.concurrent.CompletableFuture;
 
+@NonNullForAll
 public class Application extends android.app.Application implements SharedPreferences.OnSharedPreferenceChangeListener {
     private static final String TAG = "WireGuard/" + Application.class.getSimpleName();
     public static final String USER_AGENT = String.format(Locale.ENGLISH, "WireGuard/%s (Android %d; %s; %s; %s %s; %s)", BuildConfig.VERSION_NAME, Build.VERSION.SDK_INT, Build.SUPPORTED_ABIS.length > 0 ? Build.SUPPORTED_ABIS[0] : "unknown ABI", Build.BOARD, Build.MANUFACTURER, Build.MODEL, Build.FINGERPRINT);
diff --git a/ui/src/main/java/com/wireguard/android/BootShutdownReceiver.java b/ui/src/main/java/com/wireguard/android/BootShutdownReceiver.java
index e3ffce7a..f5232d50 100644
--- a/ui/src/main/java/com/wireguard/android/BootShutdownReceiver.java
+++ b/ui/src/main/java/com/wireguard/android/BootShutdownReceiver.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android;
 
+import com.wireguard.util.NonNullForAll;
+
 import android.content.BroadcastReceiver;
 import android.content.Context;
 import android.content.Intent;
@@ -14,6 +16,7 @@ import com.wireguard.android.backend.WgQuickBackend;
 import com.wireguard.android.model.TunnelManager;
 import com.wireguard.android.util.ExceptionLoggers;
 
+@NonNullForAll
 public class BootShutdownReceiver extends BroadcastReceiver {
     private static final String TAG = "WireGuard/" + BootShutdownReceiver.class.getSimpleName();
 
diff --git a/ui/src/main/java/com/wireguard/android/QuickTileService.java b/ui/src/main/java/com/wireguard/android/QuickTileService.java
index 66aecec3..f18d01b1 100644
--- a/ui/src/main/java/com/wireguard/android/QuickTileService.java
+++ b/ui/src/main/java/com/wireguard/android/QuickTileService.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android;
 
+import com.wireguard.util.NonNullForAll;
+
 import android.content.Intent;
 import androidx.databinding.Observable;
 import androidx.databinding.Observable.OnPropertyChangedCallback;
@@ -34,6 +36,7 @@ import java.util.Objects;
  */
 
 @RequiresApi(Build.VERSION_CODES.N)
+@NonNullForAll
 public class QuickTileService extends TileService {
     private static final String TAG = "WireGuard/" + QuickTileService.class.getSimpleName();
 
diff --git a/ui/src/main/java/com/wireguard/android/activity/BaseActivity.java b/ui/src/main/java/com/wireguard/android/activity/BaseActivity.java
index 8ec58ee8..6c849412 100644
--- a/ui/src/main/java/com/wireguard/android/activity/BaseActivity.java
+++ b/ui/src/main/java/com/wireguard/android/activity/BaseActivity.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android.activity;
 
+import com.wireguard.util.NonNullForAll;
+
 import androidx.databinding.CallbackRegistry;
 import androidx.databinding.CallbackRegistry.NotifierCallback;
 import android.os.Bundle;
@@ -19,6 +21,7 @@ import java.util.Objects;
  * Base class for activities that need to remember the currently-selected tunnel.
  */
 
+@NonNullForAll
 public abstract class BaseActivity extends ThemeChangeAwareActivity {
     private static final String KEY_SELECTED_TUNNEL = "selected_tunnel";
 
diff --git a/ui/src/main/java/com/wireguard/android/activity/MainActivity.java b/ui/src/main/java/com/wireguard/android/activity/MainActivity.java
index 4c33f000..1e098809 100644
--- a/ui/src/main/java/com/wireguard/android/activity/MainActivity.java
+++ b/ui/src/main/java/com/wireguard/android/activity/MainActivity.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android.activity;
 
+import com.wireguard.util.NonNullForAll;
+
 import android.annotation.SuppressLint;
 import android.content.Intent;
 import android.os.Bundle;
@@ -31,6 +33,7 @@ import java.util.List;
  * editing the configuration and interface state of WireGuard tunnels.
  */
 
+@NonNullForAll
 public class MainActivity extends BaseActivity
         implements FragmentManager.OnBackStackChangedListener {
     @Nullable private ActionBar actionBar;
diff --git a/ui/src/main/java/com/wireguard/android/activity/SettingsActivity.java b/ui/src/main/java/com/wireguard/android/activity/SettingsActivity.java
index b597a9b1..02f6b29a 100644
--- a/ui/src/main/java/com/wireguard/android/activity/SettingsActivity.java
+++ b/ui/src/main/java/com/wireguard/android/activity/SettingsActivity.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android.activity;
 
+import com.wireguard.util.NonNullForAll;
+
 import android.content.pm.PackageManager;
 import android.os.Build;
 import android.os.Bundle;
@@ -30,6 +32,7 @@ import java.util.List;
  * Interface for changing application-global persistent settings.
  */
 
+@NonNullForAll
 public class SettingsActivity extends ThemeChangeAwareActivity {
     private final SparseArray<PermissionRequestCallback> permissionRequestCallbacks = new SparseArray<>();
     private int permissionRequestCounter;
diff --git a/ui/src/main/java/com/wireguard/android/activity/ThemeChangeAwareActivity.java b/ui/src/main/java/com/wireguard/android/activity/ThemeChangeAwareActivity.java
index c553e417..114d6f13 100644
--- a/ui/src/main/java/com/wireguard/android/activity/ThemeChangeAwareActivity.java
+++ b/ui/src/main/java/com/wireguard/android/activity/ThemeChangeAwareActivity.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android.activity;
 
+import com.wireguard.util.NonNullForAll;
+
 import android.content.SharedPreferences;
 import android.content.res.Resources;
 import android.os.Build;
@@ -18,6 +20,7 @@ import com.wireguard.android.Application;
 
 import java.lang.reflect.Field;
 
+@NonNullForAll
 public abstract class ThemeChangeAwareActivity extends AppCompatActivity implements SharedPreferences.OnSharedPreferenceChangeListener {
     private static final String TAG = "WireGuard/" + ThemeChangeAwareActivity.class.getSimpleName();
 
diff --git a/ui/src/main/java/com/wireguard/android/activity/TunnelCreatorActivity.java b/ui/src/main/java/com/wireguard/android/activity/TunnelCreatorActivity.java
index c87ec537..3149988f 100644
--- a/ui/src/main/java/com/wireguard/android/activity/TunnelCreatorActivity.java
+++ b/ui/src/main/java/com/wireguard/android/activity/TunnelCreatorActivity.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android.activity;
 
+import com.wireguard.util.NonNullForAll;
+
 import android.os.Bundle;
 import androidx.annotation.Nullable;
 
@@ -15,6 +17,7 @@ import com.wireguard.android.model.ObservableTunnel;
  * Standalone activity for creating tunnels.
  */
 
+@NonNullForAll
 public class TunnelCreatorActivity extends BaseActivity {
     @Override
     @SuppressWarnings("UnnecessaryFullyQualifiedName")
diff --git a/ui/src/main/java/com/wireguard/android/activity/TunnelToggleActivity.java b/ui/src/main/java/com/wireguard/android/activity/TunnelToggleActivity.java
index 09a34bf7..dbf156b8 100644
--- a/ui/src/main/java/com/wireguard/android/activity/TunnelToggleActivity.java
+++ b/ui/src/main/java/com/wireguard/android/activity/TunnelToggleActivity.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android.activity;
 
+import com.wireguard.util.NonNullForAll;
+
 import androidx.annotation.Nullable;
 import androidx.annotation.RequiresApi;
 import androidx.appcompat.app.AppCompatActivity;
@@ -24,6 +26,7 @@ import com.wireguard.android.backend.Tunnel.State;
 import com.wireguard.android.util.ErrorMessages;
 
 @RequiresApi(Build.VERSION_CODES.N)
+@NonNullForAll
 public class TunnelToggleActivity extends AppCompatActivity {
     private static final String TAG = "WireGuard/" + TunnelToggleActivity.class.getSimpleName();
 
diff --git a/ui/src/main/java/com/wireguard/android/configStore/ConfigStore.java b/ui/src/main/java/com/wireguard/android/configStore/ConfigStore.java
index d4761464..c4db4047 100644
--- a/ui/src/main/java/com/wireguard/android/configStore/ConfigStore.java
+++ b/ui/src/main/java/com/wireguard/android/configStore/ConfigStore.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android.configStore;
 
+import com.wireguard.util.NonNullForAll;
+
 import com.wireguard.config.Config;
 
 import java.util.Set;
@@ -13,6 +15,7 @@ import java.util.Set;
  * Interface for persistent storage providers for WireGuard configurations.
  */
 
+@NonNullForAll
 public interface ConfigStore {
     /**
      * Create a persistent tunnel, which must have a unique name within the persistent storage
diff --git a/ui/src/main/java/com/wireguard/android/configStore/FileConfigStore.java b/ui/src/main/java/com/wireguard/android/configStore/FileConfigStore.java
index 45f2f759..9eb56bde 100644
--- a/ui/src/main/java/com/wireguard/android/configStore/FileConfigStore.java
+++ b/ui/src/main/java/com/wireguard/android/configStore/FileConfigStore.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android.configStore;
 
+import com.wireguard.util.NonNullForAll;
+
 import android.content.Context;
 import android.util.Log;
 
@@ -27,6 +29,7 @@ import java9.util.stream.Stream;
  * Configuration store that uses a {@code wg-quick}-style file for each configured tunnel.
  */
 
+@NonNullForAll
 public final class FileConfigStore implements ConfigStore {
     private static final String TAG = "WireGuard/" + FileConfigStore.class.getSimpleName();
 
diff --git a/ui/src/main/java/com/wireguard/android/databinding/BindingAdapters.java b/ui/src/main/java/com/wireguard/android/databinding/BindingAdapters.java
index ee216d4c..616f665d 100644
--- a/ui/src/main/java/com/wireguard/android/databinding/BindingAdapters.java
+++ b/ui/src/main/java/com/wireguard/android/databinding/BindingAdapters.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android.databinding;
 
+import com.wireguard.util.NonNullForAll;
+
 import androidx.databinding.BindingAdapter;
 import androidx.databinding.DataBindingUtil;
 import androidx.databinding.ObservableList;
@@ -35,6 +37,7 @@ import java9.util.Optional;
  */
 
 @SuppressWarnings("unused")
+@NonNullForAll
 public final class BindingAdapters {
     private BindingAdapters() {
         // Prevent instantiation.
diff --git a/ui/src/main/java/com/wireguard/android/databinding/ItemChangeListener.java b/ui/src/main/java/com/wireguard/android/databinding/ItemChangeListener.java
index e7303eae..284f73b4 100644
--- a/ui/src/main/java/com/wireguard/android/databinding/ItemChangeListener.java
+++ b/ui/src/main/java/com/wireguard/android/databinding/ItemChangeListener.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android.databinding;
 
+import com.wireguard.util.NonNullForAll;
+
 import androidx.databinding.DataBindingUtil;
 import androidx.databinding.ObservableList;
 import androidx.databinding.ViewDataBinding;
@@ -22,6 +24,7 @@ import java.util.Objects;
  * Helper class for binding an ObservableList to the children of a ViewGroup.
  */
 
+@NonNullForAll
 class ItemChangeListener<T> {
     private final OnListChangedCallback<T> callback = new OnListChangedCallback<>(this);
     private final ViewGroup container;
diff --git a/ui/src/main/java/com/wireguard/android/databinding/ObservableKeyedRecyclerViewAdapter.java b/ui/src/main/java/com/wireguard/android/databinding/ObservableKeyedRecyclerViewAdapter.java
index 8b40dd91..36d1917a 100644
--- a/ui/src/main/java/com/wireguard/android/databinding/ObservableKeyedRecyclerViewAdapter.java
+++ b/ui/src/main/java/com/wireguard/android/databinding/ObservableKeyedRecyclerViewAdapter.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android.databinding;
 
+import com.wireguard.util.NonNullForAll;
+
 import android.content.Context;
 import androidx.databinding.DataBindingUtil;
 import androidx.databinding.ObservableList;
@@ -25,6 +27,7 @@ import java.lang.ref.WeakReference;
  * A generic {@code RecyclerView.Adapter} backed by a {@code ObservableKeyedList}.
  */
 
+@NonNullForAll
 public class ObservableKeyedRecyclerViewAdapter<K, E extends Keyed<? extends K>> extends Adapter<ObservableKeyedRecyclerViewAdapter.ViewHolder> {
 
     private final OnListChangedCallback<E> callback = new OnListChangedCallback<>(this);
diff --git a/ui/src/main/java/com/wireguard/android/fragment/AppListDialogFragment.java b/ui/src/main/java/com/wireguard/android/fragment/AppListDialogFragment.java
index 43178665..e806615c 100644
--- a/ui/src/main/java/com/wireguard/android/fragment/AppListDialogFragment.java
+++ b/ui/src/main/java/com/wireguard/android/fragment/AppListDialogFragment.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android.fragment;
 
+import com.wireguard.util.NonNullForAll;
+
 import android.app.Activity;
 import android.app.Dialog;
 import android.content.DialogInterface;
@@ -34,6 +36,7 @@ import java9.util.Comparators;
 import java9.util.stream.Collectors;
 import java9.util.stream.StreamSupport;
 
+@NonNullForAll
 public class AppListDialogFragment extends DialogFragment {
 
     private static final String KEY_EXCLUDED_APPS = "excludedApps";
diff --git a/ui/src/main/java/com/wireguard/android/fragment/BaseFragment.java b/ui/src/main/java/com/wireguard/android/fragment/BaseFragment.java
index 23bf44e7..6fc6d25b 100644
--- a/ui/src/main/java/com/wireguard/android/fragment/BaseFragment.java
+++ b/ui/src/main/java/com/wireguard/android/fragment/BaseFragment.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android.fragment;
 
+import com.wireguard.util.NonNullForAll;
+
 import android.content.Context;
 import android.content.Intent;
 import androidx.databinding.DataBindingUtil;
@@ -32,6 +34,7 @@ import com.wireguard.android.util.ErrorMessages;
  * attached to a {@code BaseActivity}.
  */
 
+@NonNullForAll
 public abstract class BaseFragment extends Fragment implements OnSelectedTunnelChangedListener {
     private static final int REQUEST_CODE_VPN_PERMISSION = 23491;
     private static final String TAG = "WireGuard/" + BaseFragment.class.getSimpleName();
diff --git a/ui/src/main/java/com/wireguard/android/fragment/ConfigNamingDialogFragment.java b/ui/src/main/java/com/wireguard/android/fragment/ConfigNamingDialogFragment.java
index effa0593..113af0ab 100644
--- a/ui/src/main/java/com/wireguard/android/fragment/ConfigNamingDialogFragment.java
+++ b/ui/src/main/java/com/wireguard/android/fragment/ConfigNamingDialogFragment.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android.fragment;
 
+import com.wireguard.util.NonNullForAll;
+
 import android.app.Activity;
 import android.app.Dialog;
 import android.content.Context;
@@ -26,6 +28,7 @@ import java.io.IOException;
 import java.nio.charset.StandardCharsets;
 import java.util.Objects;
 
+@NonNullForAll
 public class ConfigNamingDialogFragment extends DialogFragment {
     private static final String KEY_CONFIG_TEXT = "config_text";
 
diff --git a/ui/src/main/java/com/wireguard/android/fragment/TunnelDetailFragment.java b/ui/src/main/java/com/wireguard/android/fragment/TunnelDetailFragment.java
index 8d90fa7e..a7ebb5d1 100644
--- a/ui/src/main/java/com/wireguard/android/fragment/TunnelDetailFragment.java
+++ b/ui/src/main/java/com/wireguard/android/fragment/TunnelDetailFragment.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android.fragment;
 
+import com.wireguard.util.NonNullForAll;
+
 import android.os.Bundle;
 import androidx.annotation.Nullable;
 import androidx.databinding.DataBindingUtil;
@@ -30,6 +32,7 @@ import java.util.TimerTask;
  * Fragment that shows details about a specific tunnel.
  */
 
+@NonNullForAll
 public class TunnelDetailFragment extends BaseFragment {
     @Nullable private TunnelDetailFragmentBinding binding;
     @Nullable private Timer timer;
diff --git a/ui/src/main/java/com/wireguard/android/fragment/TunnelEditorFragment.java b/ui/src/main/java/com/wireguard/android/fragment/TunnelEditorFragment.java
index 92aeb52a..397882d1 100644
--- a/ui/src/main/java/com/wireguard/android/fragment/TunnelEditorFragment.java
+++ b/ui/src/main/java/com/wireguard/android/fragment/TunnelEditorFragment.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android.fragment;
 
+import com.wireguard.util.NonNullForAll;
+
 import android.app.Activity;
 import android.content.Context;
 import androidx.databinding.ObservableList;
@@ -41,6 +43,7 @@ import java.util.Objects;
  * Fragment for editing a WireGuard configuration.
  */
 
+@NonNullForAll
 public class TunnelEditorFragment extends BaseFragment implements AppExclusionListener {
     private static final String KEY_LOCAL_CONFIG = "local_config";
     private static final String KEY_ORIGINAL_NAME = "original_name";
diff --git a/ui/src/main/java/com/wireguard/android/fragment/TunnelListFragment.java b/ui/src/main/java/com/wireguard/android/fragment/TunnelListFragment.java
index 21618e60..747f69fa 100644
--- a/ui/src/main/java/com/wireguard/android/fragment/TunnelListFragment.java
+++ b/ui/src/main/java/com/wireguard/android/fragment/TunnelListFragment.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android.fragment;
 
+import com.wireguard.util.NonNullForAll;
+
 import android.annotation.SuppressLint;
 import android.app.Activity;
 import android.content.ContentResolver;
@@ -64,6 +66,7 @@ import java9.util.stream.StreamSupport;
  * Fragment containing a list of known WireGuard tunnels. It allows creating and deleting tunnels.
  */
 
+@NonNullForAll
 public class TunnelListFragment extends BaseFragment {
     public static final int REQUEST_IMPORT = 1;
     private static final int REQUEST_TARGET_FRAGMENT = 2;
diff --git a/ui/src/main/java/com/wireguard/android/model/ApplicationData.java b/ui/src/main/java/com/wireguard/android/model/ApplicationData.java
index 65edff90..a64d9d71 100644
--- a/ui/src/main/java/com/wireguard/android/model/ApplicationData.java
+++ b/ui/src/main/java/com/wireguard/android/model/ApplicationData.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android.model;
 
+import com.wireguard.util.NonNullForAll;
+
 import androidx.databinding.BaseObservable;
 import androidx.databinding.Bindable;
 import android.graphics.drawable.Drawable;
@@ -12,6 +14,7 @@ import android.graphics.drawable.Drawable;
 import com.wireguard.android.BR;
 import com.wireguard.util.Keyed;
 
+@NonNullForAll
 public class ApplicationData extends BaseObservable implements Keyed<String> {
     private final Drawable icon;
     private final String name;
diff --git a/ui/src/main/java/com/wireguard/android/model/ObservableTunnel.java b/ui/src/main/java/com/wireguard/android/model/ObservableTunnel.java
index edd8bd68..70e3bac9 100644
--- a/ui/src/main/java/com/wireguard/android/model/ObservableTunnel.java
+++ b/ui/src/main/java/com/wireguard/android/model/ObservableTunnel.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android.model;
 
+import com.wireguard.util.NonNullForAll;
+
 import androidx.databinding.BaseObservable;
 import androidx.databinding.Bindable;
 import androidx.annotation.Nullable;
@@ -23,6 +25,7 @@ import java9.util.concurrent.CompletionStage;
  * Encapsulates the volatile and nonvolatile state of a WireGuard tunnel.
  */
 
+@NonNullForAll
 public class ObservableTunnel extends BaseObservable implements Keyed<String>, Tunnel {
     private final TunnelManager manager;
     @Nullable private Config config;
diff --git a/ui/src/main/java/com/wireguard/android/model/TunnelManager.java b/ui/src/main/java/com/wireguard/android/model/TunnelManager.java
index 35d56c81..77304091 100644
--- a/ui/src/main/java/com/wireguard/android/model/TunnelManager.java
+++ b/ui/src/main/java/com/wireguard/android/model/TunnelManager.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android.model;
 
+import com.wireguard.util.NonNullForAll;
+
 import android.content.BroadcastReceiver;
 import android.content.Context;
 import android.content.Intent;
@@ -39,6 +41,7 @@ import java9.util.stream.StreamSupport;
  * Maintains and mediates changes to the set of available WireGuard tunnels,
  */
 
+@NonNullForAll
 public final class TunnelManager extends BaseObservable {
     private static final Comparator<String> COMPARATOR = Comparators.<String>thenComparing(
             String.CASE_INSENSITIVE_ORDER, Comparators.naturalOrder());
diff --git a/ui/src/main/java/com/wireguard/android/preference/LogExporterPreference.java b/ui/src/main/java/com/wireguard/android/preference/LogExporterPreference.java
index 565854b4..69608e4d 100644
--- a/ui/src/main/java/com/wireguard/android/preference/LogExporterPreference.java
+++ b/ui/src/main/java/com/wireguard/android/preference/LogExporterPreference.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android.preference;
 
+import com.wireguard.util.NonNullForAll;
+
 import android.Manifest;
 import android.content.Context;
 import android.content.pm.PackageManager;
@@ -29,6 +31,7 @@ import java.io.InputStreamReader;
  * Preference implementing a button that asynchronously exports logs.
  */
 
+@NonNullForAll
 public class LogExporterPreference extends Preference {
     private static final String TAG = "WireGuard/" + LogExporterPreference.class.getSimpleName();
 
diff --git a/ui/src/main/java/com/wireguard/android/preference/ModuleDownloaderPreference.java b/ui/src/main/java/com/wireguard/android/preference/ModuleDownloaderPreference.java
index 5c83f1dc..8858c725 100644
--- a/ui/src/main/java/com/wireguard/android/preference/ModuleDownloaderPreference.java
+++ b/ui/src/main/java/com/wireguard/android/preference/ModuleDownloaderPreference.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android.preference;
 
+import com.wireguard.util.NonNullForAll;
+
 import android.content.Context;
 import android.content.Intent;
 import android.system.OsConstants;
@@ -18,6 +20,7 @@ import com.wireguard.android.util.ErrorMessages;
 import androidx.annotation.Nullable;
 import androidx.preference.Preference;
 
+@NonNullForAll
 public class ModuleDownloaderPreference extends Preference {
     private State state = State.INITIAL;
 
diff --git a/ui/src/main/java/com/wireguard/android/preference/ToolsInstallerPreference.java b/ui/src/main/java/com/wireguard/android/preference/ToolsInstallerPreference.java
index 78a7497b..61752598 100644
--- a/ui/src/main/java/com/wireguard/android/preference/ToolsInstallerPreference.java
+++ b/ui/src/main/java/com/wireguard/android/preference/ToolsInstallerPreference.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android.preference;
 
+import com.wireguard.util.NonNullForAll;
+
 import android.content.Context;
 import androidx.annotation.Nullable;
 import androidx.preference.Preference;
@@ -19,6 +21,7 @@ import com.wireguard.android.util.ToolsInstaller;
  * result as the preference summary.
  */
 
+@NonNullForAll
 public class ToolsInstallerPreference extends Preference {
     private State state = State.INITIAL;
 
diff --git a/ui/src/main/java/com/wireguard/android/preference/VersionPreference.java b/ui/src/main/java/com/wireguard/android/preference/VersionPreference.java
index 7e95a8ae..542fe2d2 100644
--- a/ui/src/main/java/com/wireguard/android/preference/VersionPreference.java
+++ b/ui/src/main/java/com/wireguard/android/preference/VersionPreference.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android.preference;
 
+import com.wireguard.util.NonNullForAll;
+
 import android.content.ActivityNotFoundException;
 import android.content.Context;
 import android.content.Intent;
@@ -22,6 +24,7 @@ import com.wireguard.android.backend.WgQuickBackend;
 
 import java.util.Locale;
 
+@NonNullForAll
 public class VersionPreference extends Preference {
     @Nullable private String versionSummary;
 
diff --git a/ui/src/main/java/com/wireguard/android/preference/ZipExporterPreference.java b/ui/src/main/java/com/wireguard/android/preference/ZipExporterPreference.java
index 3af412a5..8f86fec7 100644
--- a/ui/src/main/java/com/wireguard/android/preference/ZipExporterPreference.java
+++ b/ui/src/main/java/com/wireguard/android/preference/ZipExporterPreference.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android.preference;
 
+import com.wireguard.util.NonNullForAll;
+
 import android.Manifest;
 import android.content.Context;
 import android.content.pm.PackageManager;
@@ -35,6 +37,7 @@ import java9.util.concurrent.CompletableFuture;
  * Preference implementing a button that asynchronously exports config zips.
  */
 
+@NonNullForAll
 public class ZipExporterPreference extends Preference {
     private static final String TAG = "WireGuard/" + ZipExporterPreference.class.getSimpleName();
 
diff --git a/ui/src/main/java/com/wireguard/android/util/AsyncWorker.java b/ui/src/main/java/com/wireguard/android/util/AsyncWorker.java
index 1d041851..f8341976 100644
--- a/ui/src/main/java/com/wireguard/android/util/AsyncWorker.java
+++ b/ui/src/main/java/com/wireguard/android/util/AsyncWorker.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android.util;
 
+import com.wireguard.util.NonNullForAll;
+
 import android.os.Handler;
 
 import java.util.concurrent.Executor;
@@ -16,6 +18,7 @@ import java9.util.concurrent.CompletionStage;
  * Helper class for running asynchronous tasks and ensuring they are completed on the main thread.
  */
 
+@NonNullForAll
 public class AsyncWorker {
     private final Executor executor;
     private final Handler handler;
diff --git a/ui/src/main/java/com/wireguard/android/util/ClipboardUtils.java b/ui/src/main/java/com/wireguard/android/util/ClipboardUtils.java
index 0df5e96a..649fe261 100644
--- a/ui/src/main/java/com/wireguard/android/util/ClipboardUtils.java
+++ b/ui/src/main/java/com/wireguard/android/util/ClipboardUtils.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android.util;
 
+import com.wireguard.util.NonNullForAll;
+
 import android.content.ClipData;
 import android.content.ClipboardManager;
 import android.content.Context;
@@ -16,6 +18,7 @@ import android.widget.TextView;
  * Standalone utilities for interacting with the system clipboard.
  */
 
+@NonNullForAll
 public final class ClipboardUtils {
     private ClipboardUtils() {
         // Prevent instantiation
diff --git a/ui/src/main/java/com/wireguard/android/util/DownloadsFileSaver.java b/ui/src/main/java/com/wireguard/android/util/DownloadsFileSaver.java
index 7db46fa9..3f80a562 100644
--- a/ui/src/main/java/com/wireguard/android/util/DownloadsFileSaver.java
+++ b/ui/src/main/java/com/wireguard/android/util/DownloadsFileSaver.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android.util;
 
+import com.wireguard.util.NonNullForAll;
+
 import android.content.ContentResolver;
 import android.content.ContentValues;
 import android.content.Context;
@@ -22,6 +24,7 @@ import java.io.FileOutputStream;
 import java.io.IOException;
 import java.io.OutputStream;
 
+@NonNullForAll
 public class DownloadsFileSaver {
 
     public static class DownloadsFile {
diff --git a/ui/src/main/java/com/wireguard/android/util/ErrorMessages.java b/ui/src/main/java/com/wireguard/android/util/ErrorMessages.java
index 481a6ffb..3b818251 100644
--- a/ui/src/main/java/com/wireguard/android/util/ErrorMessages.java
+++ b/ui/src/main/java/com/wireguard/android/util/ErrorMessages.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android.util;
 
+import com.wireguard.util.NonNullForAll;
+
 import android.content.res.Resources;
 import android.os.RemoteException;
 
@@ -29,6 +31,7 @@ import java.util.Map;
 
 import java9.util.Maps;
 
+@NonNullForAll
 public final class ErrorMessages {
     private static final Map<BadConfigException.Reason, Integer> BCE_REASON_MAP = new EnumMap<>(Maps.of(
             BadConfigException.Reason.INVALID_KEY, R.string.bad_config_reason_invalid_key,
diff --git a/ui/src/main/java/com/wireguard/android/util/ExceptionLoggers.java b/ui/src/main/java/com/wireguard/android/util/ExceptionLoggers.java
index 5c7a38c0..3e56bd55 100644
--- a/ui/src/main/java/com/wireguard/android/util/ExceptionLoggers.java
+++ b/ui/src/main/java/com/wireguard/android/util/ExceptionLoggers.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android.util;
 
+import com.wireguard.util.NonNullForAll;
+
 import androidx.annotation.Nullable;
 import android.util.Log;
 
diff --git a/ui/src/main/java/com/wireguard/android/util/FragmentUtils.java b/ui/src/main/java/com/wireguard/android/util/FragmentUtils.java
index 5fb9a3bc..50a49fa1 100644
--- a/ui/src/main/java/com/wireguard/android/util/FragmentUtils.java
+++ b/ui/src/main/java/com/wireguard/android/util/FragmentUtils.java
@@ -4,12 +4,15 @@
  */
 package com.wireguard.android.util;
 
+import com.wireguard.util.NonNullForAll;
+
 import android.content.Context;
 import androidx.preference.Preference;
 import android.view.ContextThemeWrapper;
 
 import com.wireguard.android.activity.SettingsActivity;
 
+@NonNullForAll
 public final class FragmentUtils {
     private FragmentUtils() {
         // Prevent instantiation
diff --git a/ui/src/main/java/com/wireguard/android/util/ObservableKeyedArrayList.java b/ui/src/main/java/com/wireguard/android/util/ObservableKeyedArrayList.java
index 0ba02184..bf16d921 100644
--- a/ui/src/main/java/com/wireguard/android/util/ObservableKeyedArrayList.java
+++ b/ui/src/main/java/com/wireguard/android/util/ObservableKeyedArrayList.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android.util;
 
+import com.wireguard.util.NonNullForAll;
+
 import androidx.databinding.ObservableArrayList;
 import androidx.annotation.Nullable;
 
@@ -21,6 +23,7 @@ import java.util.Objects;
  * operations, require O(n) time.
  */
 
+@NonNullForAll
 public class ObservableKeyedArrayList<K, E extends Keyed<? extends K>>
         extends ObservableArrayList<E> implements ObservableKeyedList<K, E> {
     @Override
diff --git a/ui/src/main/java/com/wireguard/android/util/ObservableKeyedList.java b/ui/src/main/java/com/wireguard/android/util/ObservableKeyedList.java
index be8ceb9b..1c430493 100644
--- a/ui/src/main/java/com/wireguard/android/util/ObservableKeyedList.java
+++ b/ui/src/main/java/com/wireguard/android/util/ObservableKeyedList.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android.util;
 
+import com.wireguard.util.NonNullForAll;
+
 import androidx.databinding.ObservableList;
 
 import com.wireguard.util.Keyed;
@@ -14,6 +16,7 @@ import com.wireguard.util.KeyedList;
  * A list that is both keyed and observable.
  */
 
+@NonNullForAll
 public interface ObservableKeyedList<K, E extends Keyed<? extends K>>
         extends KeyedList<K, E>, ObservableList<E> {
 }
diff --git a/ui/src/main/java/com/wireguard/android/util/ObservableSortedKeyedArrayList.java b/ui/src/main/java/com/wireguard/android/util/ObservableSortedKeyedArrayList.java
index 1d585856..77d6bbf3 100644
--- a/ui/src/main/java/com/wireguard/android/util/ObservableSortedKeyedArrayList.java
+++ b/ui/src/main/java/com/wireguard/android/util/ObservableSortedKeyedArrayList.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android.util;
 
+import com.wireguard.util.NonNullForAll;
+
 import androidx.annotation.Nullable;
 
 import com.wireguard.util.Keyed;
@@ -26,6 +28,7 @@ import java.util.Spliterator;
  * key still require O(n) time.
  */
 
+@NonNullForAll
 public class ObservableSortedKeyedArrayList<K, E extends Keyed<? extends K>>
         extends ObservableKeyedArrayList<K, E> implements ObservableSortedKeyedList<K, E> {
     @Nullable private final Comparator<? super K> comparator;
diff --git a/ui/src/main/java/com/wireguard/android/util/ObservableSortedKeyedList.java b/ui/src/main/java/com/wireguard/android/util/ObservableSortedKeyedList.java
index d796704e..59531408 100644
--- a/ui/src/main/java/com/wireguard/android/util/ObservableSortedKeyedList.java
+++ b/ui/src/main/java/com/wireguard/android/util/ObservableSortedKeyedList.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android.util;
 
+import com.wireguard.util.NonNullForAll;
+
 import com.wireguard.util.Keyed;
 import com.wireguard.util.SortedKeyedList;
 
@@ -12,6 +14,7 @@ import com.wireguard.util.SortedKeyedList;
  * A list that is both sorted/keyed and observable.
  */
 
+@NonNullForAll
 public interface ObservableSortedKeyedList<K, E extends Keyed<? extends K>>
         extends ObservableKeyedList<K, E>, SortedKeyedList<K, E> {
 }
diff --git a/ui/src/main/java/com/wireguard/android/viewmodel/ConfigProxy.java b/ui/src/main/java/com/wireguard/android/viewmodel/ConfigProxy.java
index bcfe14e3..cc7bc082 100644
--- a/ui/src/main/java/com/wireguard/android/viewmodel/ConfigProxy.java
+++ b/ui/src/main/java/com/wireguard/android/viewmodel/ConfigProxy.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android.viewmodel;
 
+import com.wireguard.util.NonNullForAll;
+
 import androidx.databinding.ObservableArrayList;
 import androidx.databinding.ObservableList;
 import android.os.Parcel;
@@ -17,6 +19,7 @@ import com.wireguard.config.Peer;
 import java.util.ArrayList;
 import java.util.Collection;
 
+@NonNullForAll
 public class ConfigProxy implements Parcelable {
     public static final Parcelable.Creator<ConfigProxy> CREATOR = new ConfigProxyCreator();
 
diff --git a/ui/src/main/java/com/wireguard/android/viewmodel/InterfaceProxy.java b/ui/src/main/java/com/wireguard/android/viewmodel/InterfaceProxy.java
index cc9f2dd8..da9c4f10 100644
--- a/ui/src/main/java/com/wireguard/android/viewmodel/InterfaceProxy.java
+++ b/ui/src/main/java/com/wireguard/android/viewmodel/InterfaceProxy.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android.viewmodel;
 
+import com.wireguard.util.NonNullForAll;
+
 import androidx.databinding.BaseObservable;
 import androidx.databinding.Bindable;
 import androidx.databinding.ObservableArrayList;
@@ -26,6 +28,7 @@ import java.util.List;
 import java9.util.stream.Collectors;
 import java9.util.stream.StreamSupport;
 
+@NonNullForAll
 public class InterfaceProxy extends BaseObservable implements Parcelable {
     public static final Parcelable.Creator<InterfaceProxy> CREATOR = new InterfaceProxyCreator();
 
diff --git a/ui/src/main/java/com/wireguard/android/viewmodel/PeerProxy.java b/ui/src/main/java/com/wireguard/android/viewmodel/PeerProxy.java
index 7dc50f09..7fc614a1 100644
--- a/ui/src/main/java/com/wireguard/android/viewmodel/PeerProxy.java
+++ b/ui/src/main/java/com/wireguard/android/viewmodel/PeerProxy.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android.viewmodel;
 
+import com.wireguard.util.NonNullForAll;
+
 import androidx.databinding.BaseObservable;
 import androidx.databinding.Bindable;
 import androidx.databinding.Observable;
@@ -32,6 +34,7 @@ import java9.util.Sets;
 import java9.util.stream.Collectors;
 import java9.util.stream.Stream;
 
+@NonNullForAll
 public class PeerProxy extends BaseObservable implements Parcelable {
     public static final Parcelable.Creator<PeerProxy> CREATOR = new PeerProxyCreator();
     private static final Set<String> IPV4_PUBLIC_NETWORKS = new LinkedHashSet<>(Lists.of(
diff --git a/ui/src/main/java/com/wireguard/android/widget/KeyInputFilter.java b/ui/src/main/java/com/wireguard/android/widget/KeyInputFilter.java
index 79572aa3..c91b12ff 100644
--- a/ui/src/main/java/com/wireguard/android/widget/KeyInputFilter.java
+++ b/ui/src/main/java/com/wireguard/android/widget/KeyInputFilter.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android.widget;
 
+import com.wireguard.util.NonNullForAll;
+
 import androidx.annotation.Nullable;
 import android.text.InputFilter;
 import android.text.SpannableStringBuilder;
@@ -16,6 +18,7 @@ import com.wireguard.crypto.Key;
  * InputFilter for entering WireGuard private/public keys encoded with base64.
  */
 
+@NonNullForAll
 public class KeyInputFilter implements InputFilter {
     private static boolean isAllowed(final char c) {
         return Character.isLetterOrDigit(c) || c == '+' || c == '/';
diff --git a/ui/src/main/java/com/wireguard/android/widget/MultiselectableRelativeLayout.java b/ui/src/main/java/com/wireguard/android/widget/MultiselectableRelativeLayout.java
index 2fe9c924..16742ae8 100644
--- a/ui/src/main/java/com/wireguard/android/widget/MultiselectableRelativeLayout.java
+++ b/ui/src/main/java/com/wireguard/android/widget/MultiselectableRelativeLayout.java
@@ -5,12 +5,15 @@
 
 package com.wireguard.android.widget;
 
+import com.wireguard.util.NonNullForAll;
+
 import android.content.Context;
 import android.util.AttributeSet;
 import android.widget.RelativeLayout;
 
 import com.wireguard.android.R;
 
+@NonNullForAll
 public class MultiselectableRelativeLayout extends RelativeLayout {
     private static final int[] STATE_MULTISELECTED = {R.attr.state_multiselected};
     private boolean multiselected;
diff --git a/ui/src/main/java/com/wireguard/android/widget/NameInputFilter.java b/ui/src/main/java/com/wireguard/android/widget/NameInputFilter.java
index 030be25a..1ec14ac0 100644
--- a/ui/src/main/java/com/wireguard/android/widget/NameInputFilter.java
+++ b/ui/src/main/java/com/wireguard/android/widget/NameInputFilter.java
@@ -5,6 +5,8 @@
 
 package com.wireguard.android.widget;
 
+import com.wireguard.util.NonNullForAll;
+
 import androidx.annotation.Nullable;
 import android.text.InputFilter;
 import android.text.SpannableStringBuilder;
@@ -16,6 +18,7 @@ import com.wireguard.android.backend.Tunnel;
  * InputFilter for entering WireGuard configuration names (Linux interface names).
  */
 
+@NonNullForAll
 public class NameInputFilter implements InputFilter {
     private static boolean isAllowed(final char c) {
         return Character.isLetterOrDigit(c) || "_=+.-".indexOf(c) >= 0;
diff --git a/ui/src/main/java/com/wireguard/android/widget/SlashDrawable.java b/ui/src/main/java/com/wireguard/android/widget/SlashDrawable.java
index e020aa81..4a3142ea 100644
--- a/ui/src/main/java/com/wireguard/android/widget/SlashDrawable.java
+++ b/ui/src/main/java/com/wireguard/android/widget/SlashDrawable.java
@@ -6,6 +6,8 @@
 
 package com.wireguard.android.widget;
 
+import com.wireguard.util.NonNullForAll;
+
 import android.animation.ObjectAnimator;
 import android.animation.ValueAnimator;
 import android.content.res.ColorStateList;
@@ -29,6 +31,7 @@ import androidx.annotation.RequiresApi;
 import android.util.FloatProperty;
 
 @RequiresApi(Build.VERSION_CODES.N)
+@NonNullForAll
 public class SlashDrawable extends Drawable {
 
     private static final float CENTER_X = 10.65f;
diff --git a/ui/src/main/java/com/wireguard/android/widget/ToggleSwitch.java b/ui/src/main/java/com/wireguard/android/widget/ToggleSwitch.java
index dcb9aceb..3aec3329 100644
--- a/ui/src/main/java/com/wireguard/android/widget/ToggleSwitch.java
+++ b/ui/src/main/java/com/wireguard/android/widget/ToggleSwitch.java
@@ -6,12 +6,15 @@
 
 package com.wireguard.android.widget;
 
+import com.wireguard.util.NonNullForAll;
+
 import android.content.Context;
 import android.os.Parcelable;
 import androidx.annotation.Nullable;
 import android.util.AttributeSet;
 import android.widget.Switch;
 
+@NonNullForAll
 public class ToggleSwitch extends Switch {
     private boolean isRestoringState;
     @Nullable private OnBeforeCheckedChangeListener listener;