diff --git a/res/layout-large-notouch/activity_updates.xml b/res/layout-large-notouch/activity_updates.xml
index 09823bce..f14a8038 100644
--- a/res/layout-large-notouch/activity_updates.xml
+++ b/res/layout-large-notouch/activity_updates.xml
@@ -1,13 +1,14 @@
 <?xml version="1.0" encoding="utf-8"?>
-<LinearLayout
-    xmlns:android="http://schemas.android.com/apk/res/android"
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:tools="http://schemas.android.com/tools"
     android:orientation="horizontal"
     android:id="@+id/main_container"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:fitsSystemWindows="true"
     android:padding="16dp"
-    android:weightSum="2">
+    android:weightSum="2"
+    android:baselineAligned="false">
 
     <RelativeLayout
         android:layout_width="0dp"
@@ -29,57 +30,57 @@
                 android:fontFamily="sans-serif-light"
                 android:paddingBottom="16dp"
                 android:textColor="?android:attr/textColorPrimary"
-                android:textSize="56sp" />
+                android:textSize="56sp"
+                tools:text="LineageOS\n18.1" />
 
             <TextView
                 android:id="@+id/header_build_version"
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"
-                android:layout_below="@id/header_title"
                 android:textColor="?android:attr/textColorPrimary"
-                android:textSize="14sp" />
+                android:textSize="14sp"
+                tools:text="Android 11"/>
 
             <TextView
                 android:id="@+id/header_build_date"
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"
-                android:layout_below="@id/header_build_version"
                 android:textColor="?android:attr/textColorPrimary"
-                android:textSize="14sp" />
+                android:textSize="14sp"
+                tools:text="2022-01-01"/>
 
             <TextView
                 android:id="@+id/header_last_check"
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"
-                android:layout_below="@id/header_build_date"
                 android:textColor="?android:attr/textColorPrimary"
-                android:textSize="14sp" />
+                android:textSize="14sp"
+                tools:text="Last checked: 2022-01-01"/>
 
         </LinearLayout>
         <LinearLayout
             android:layout_width="match_parent"
             android:layout_height="wrap_content"
-            android:layout_below="@id/header_last_check"
             android:layout_alignParentBottom="true"
             android:weightSum="2"
             android:orientation="horizontal">
 
             <Button
                 android:id="@+id/refresh"
-                android:drawableLeft="@drawable/ic_menu_refresh"
+                android:drawableStart="@drawable/ic_menu_refresh"
                 android:layout_width="0dp"
                 android:layout_height="wrap_content"
                 android:layout_weight="1"
-                android:text="refresh"
+                android:text="@string/menu_refresh"
                 style="@style/Widget.AppCompat.Button.Borderless.Colored"/>
 
             <Button
                 android:id="@+id/preferences"
-                android:drawableLeft="@drawable/ic_menu_preferences"
+                android:drawableStart="@drawable/ic_menu_preferences"
                 android:layout_width="0dp"
                 android:layout_height="wrap_content"
                 android:layout_weight="1"
-                android:text="preferences"
+                android:text="@string/menu_preferences"
                 style="@style/Widget.AppCompat.Button.Borderless.Colored"/>
 
         </LinearLayout>
diff --git a/res/layout-large-notouch/update_item_view.xml b/res/layout-large-notouch/update_item_view.xml
index 18973f2e..b7b7fd8a 100644
--- a/res/layout-large-notouch/update_item_view.xml
+++ b/res/layout-large-notouch/update_item_view.xml
@@ -16,7 +16,8 @@
         android:layout_width="match_parent"
         android:layout_height="match_parent"
         android:orientation="horizontal"
-        android:weightSum="1">
+        android:weightSum="1"
+        android:baselineAligned="false">
 
         <LinearLayout
             android:layout_width="0dp"
@@ -90,7 +91,8 @@
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"
                 android:layout_gravity="end"
-                android:padding="8dp" />
+                android:padding="8dp"
+                android:contentDescription="@null" />
             <Button
                 android:id="@id/update_action"
                 style="@style/Widget.AppCompat.Button.Borderless.Colored"
diff --git a/res/layout/preferences_dialog.xml b/res/layout/preferences_dialog.xml
index d78f8732..c586f44e 100644
--- a/res/layout/preferences_dialog.xml
+++ b/res/layout/preferences_dialog.xml
@@ -29,7 +29,7 @@
             android:entries="@array/menu_auto_updates_check_interval_entries" />
     </LinearLayout>
 
-    <Switch
+    <androidx.appcompat.widget.SwitchCompat
         android:id="@+id/preferences_auto_delete_updates"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
@@ -37,7 +37,7 @@
         android:text="@string/menu_auto_delete_updates"
         android:textSize="16sp" />
 
-    <Switch
+    <androidx.appcompat.widget.SwitchCompat
         android:id="@+id/preferences_mobile_data_warning"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
@@ -45,7 +45,7 @@
         android:text="@string/menu_mobile_data_warning"
         android:textSize="16sp" />
 
-    <Switch
+    <androidx.appcompat.widget.SwitchCompat
         android:id="@+id/preferences_ab_perf_mode"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
@@ -53,7 +53,7 @@
         android:text="@string/menu_ab_perf_mode"
         android:textSize="16sp" />
 
-    <Switch
+    <androidx.appcompat.widget.SwitchCompat
         android:id="@+id/preferences_update_recovery"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
diff --git a/res/layout/update_item_view.xml b/res/layout/update_item_view.xml
index 83de4870..2f04ba61 100644
--- a/res/layout/update_item_view.xml
+++ b/res/layout/update_item_view.xml
@@ -15,7 +15,8 @@
         android:layout_width="match_parent"
         android:layout_height="match_parent"
         android:orientation="horizontal"
-        android:weightSum="1">
+        android:weightSum="1"
+        android:baselineAligned="false">
 
         <LinearLayout
             android:layout_width="0dp"
@@ -89,7 +90,8 @@
                 android:layout_width="wrap_content"
                 android:layout_height="wrap_content"
                 android:layout_gravity="end"
-                android:padding="8dp" />
+                android:padding="8dp"
+                android:contentDescription="@null" />
             <Button
                 android:id="@id/update_action"
                 style="@style/Widget.AppCompat.Button.Borderless.Colored"
diff --git a/res/menu/menu_action_mode.xml b/res/menu/menu_action_mode.xml
index 4af76603..3ee59ce6 100644
--- a/res/menu/menu_action_mode.xml
+++ b/res/menu/menu_action_mode.xml
@@ -1,6 +1,5 @@
 <?xml version="1.0" encoding="utf-8"?>
-<menu xmlns:android="http://schemas.android.com/apk/res/android"
-    xmlns:app="http://schemas.android.com/apk/res-auto">
+<menu xmlns:android="http://schemas.android.com/apk/res/android">
     <item
         android:id="@+id/menu_export_update"
         android:title="@string/menu_export_update" />
diff --git a/src/org/lineageos/updater/ExportUpdateService.java b/src/org/lineageos/updater/ExportUpdateService.java
index 2406d2fd..4f3a8288 100644
--- a/src/org/lineageos/updater/ExportUpdateService.java
+++ b/src/org/lineageos/updater/ExportUpdateService.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2017 The LineageOS Project
+ * Copyright (C) 2017-2022 The LineageOS Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -94,11 +94,11 @@ public class ExportUpdateService extends Service {
     }
 
     private class ExportRunnable implements Runnable {
-        private File mSource;
-        private File mDestination;
-        private FileUtils.ProgressCallBack mProgressCallBack;
-        private Runnable mRunnableComplete;
-        private Runnable mRunnableFailed;
+        private final File mSource;
+        private final File mDestination;
+        private final FileUtils.ProgressCallBack mProgressCallBack;
+        private final Runnable mRunnableComplete;
+        private final Runnable mRunnableFailed;
 
         private ExportRunnable(File source, File destination,
                 FileUtils.ProgressCallBack progressCallBack,
@@ -131,13 +131,13 @@ public class ExportUpdateService extends Service {
         }
 
         private void cleanUp() {
+            //noinspection ResultOfMethodCallIgnored
             mDestination.delete();
         }
     }
 
     private void startExporting(File source, File destination) {
-        NotificationManager notificationManager =
-                (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
+        NotificationManager notificationManager = getSystemService(NotificationManager.class);
         NotificationChannel notificationChannel = new NotificationChannel(
                 EXPORT_NOTIFICATION_CHANNEL,
                 getString(R.string.export_channel_title),
diff --git a/src/org/lineageos/updater/UpdaterReceiver.java b/src/org/lineageos/updater/UpdaterReceiver.java
index 51b87d0d..643fc370 100644
--- a/src/org/lineageos/updater/UpdaterReceiver.java
+++ b/src/org/lineageos/updater/UpdaterReceiver.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2017 The LineageOS Project
+ * Copyright (C) 2017-2022 The LineageOS Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -79,8 +79,7 @@ public class UpdaterReceiver extends BroadcastReceiver {
                 .setStyle(new NotificationCompat.BigTextStyle().bigText(buildInfo))
                 .setContentText(buildInfo);
 
-        NotificationManager nm = (NotificationManager) context.getSystemService(
-                Context.NOTIFICATION_SERVICE);
+        NotificationManager nm = context.getSystemService(NotificationManager.class);
         nm.createNotificationChannel(notificationChannel);
         nm.notify(0, builder.build());
     }
@@ -88,7 +87,7 @@ public class UpdaterReceiver extends BroadcastReceiver {
     @Override
     public void onReceive(Context context, Intent intent) {
         if (ACTION_INSTALL_REBOOT.equals(intent.getAction())) {
-            PowerManager pm = (PowerManager) context.getSystemService(Context.POWER_SERVICE);
+            PowerManager pm = context.getSystemService(PowerManager.class);
             pm.reboot(null);
         } else if (Intent.ACTION_BOOT_COMPLETED.equals(intent.getAction())) {
             SharedPreferences pref = PreferenceManager.getDefaultSharedPreferences(context);
diff --git a/src/org/lineageos/updater/UpdatesActivity.java b/src/org/lineageos/updater/UpdatesActivity.java
index 32d31f99..395e801b 100644
--- a/src/org/lineageos/updater/UpdatesActivity.java
+++ b/src/org/lineageos/updater/UpdatesActivity.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2017-2020 The LineageOS Project
+ * Copyright (C) 2017-2022 The LineageOS Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -15,6 +15,7 @@
  */
 package org.lineageos.updater;
 
+import android.annotation.SuppressLint;
 import android.app.UiModeManager;
 import android.content.BroadcastReceiver;
 import android.content.ComponentName;
@@ -39,14 +40,13 @@ import android.view.View;
 import android.view.animation.Animation;
 import android.view.animation.LinearInterpolator;
 import android.view.animation.RotateAnimation;
-import android.widget.Button;
 import android.widget.Spinner;
-import android.widget.Switch;
 import android.widget.TextView;
 import android.widget.Toast;
 
+import androidx.appcompat.app.ActionBar;
 import androidx.appcompat.app.AlertDialog;
-import androidx.appcompat.app.AppCompatDelegate;
+import androidx.appcompat.widget.SwitchCompat;
 import androidx.appcompat.widget.Toolbar;
 import androidx.localbroadcastmanager.content.LocalBroadcastManager;
 import androidx.preference.PreferenceManager;
@@ -92,10 +92,10 @@ public class UpdatesActivity extends UpdatesListActivity {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_updates);
 
-        UiModeManager uiModeManager = (UiModeManager) getSystemService(UI_MODE_SERVICE);
+        UiModeManager uiModeManager = getSystemService(UiModeManager.class);
         mIsTV = uiModeManager.getCurrentModeType() == Configuration.UI_MODE_TYPE_TELEVISION;
 
-        RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recycler_view);
+        RecyclerView recyclerView = findViewById(R.id.recycler_view);
         mAdapter = new UpdatesListAdapter(this);
         recyclerView.setAdapter(mAdapter);
         RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(this);
@@ -111,7 +111,7 @@ public class UpdatesActivity extends UpdatesListActivity {
                 if (UpdaterController.ACTION_UPDATE_STATUS.equals(intent.getAction())) {
                     String downloadId = intent.getStringExtra(UpdaterController.EXTRA_DOWNLOAD_ID);
                     handleDownloadStatusChange(downloadId);
-                    mAdapter.notifyDataSetChanged();
+                    mAdapter.notifyItemChanged(downloadId);
                 } else if (UpdaterController.ACTION_DOWNLOAD_PROGRESS.equals(intent.getAction()) ||
                         UpdaterController.ACTION_INSTALL_PROGRESS.equals(intent.getAction())) {
                     String downloadId = intent.getStringExtra(UpdaterController.EXTRA_DOWNLOAD_ID);
@@ -124,31 +124,33 @@ public class UpdatesActivity extends UpdatesListActivity {
         };
 
         if (!mIsTV) {
-            Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
+            Toolbar toolbar = findViewById(R.id.toolbar);
             setSupportActionBar(toolbar);
-            getSupportActionBar().setDisplayShowTitleEnabled(false);
-            getSupportActionBar().setDisplayHomeAsUpEnabled(true);
+            ActionBar actionBar = getSupportActionBar();
+            if (actionBar != null) {
+                actionBar.setDisplayShowTitleEnabled(false);
+                actionBar.setDisplayHomeAsUpEnabled(true);
+            }
         }
 
-        TextView headerTitle = (TextView) findViewById(R.id.header_title);
+        TextView headerTitle = findViewById(R.id.header_title);
         headerTitle.setText(getString(R.string.header_title_text,
                 BuildInfoUtils.getBuildVersion()));
 
         updateLastCheckedString();
 
-        TextView headerBuildVersion = (TextView) findViewById(R.id.header_build_version);
+        TextView headerBuildVersion = findViewById(R.id.header_build_version);
         headerBuildVersion.setText(
                 getString(R.string.header_android_version, Build.VERSION.RELEASE));
 
-        TextView headerBuildDate = (TextView) findViewById(R.id.header_build_date);
+        TextView headerBuildDate = findViewById(R.id.header_build_date);
         headerBuildDate.setText(StringGenerator.getDateLocalizedUTC(this,
                 DateFormat.LONG, BuildInfoUtils.getBuildDateTimestamp()));
 
         if (!mIsTV) {
             // Switch between header title and appbar title minimizing overlaps
-            final CollapsingToolbarLayout collapsingToolbar =
-                    (CollapsingToolbarLayout) findViewById(R.id.collapsing_toolbar);
-            final AppBarLayout appBar = (AppBarLayout) findViewById(R.id.app_bar);
+            final CollapsingToolbarLayout collapsingToolbar = findViewById(R.id.collapsing_toolbar);
+            final AppBarLayout appBar = findViewById(R.id.app_bar);
             appBar.addOnOffsetChangedListener(new AppBarLayout.OnOffsetChangedListener() {
                 boolean mIsShown = false;
 
@@ -175,18 +177,8 @@ public class UpdatesActivity extends UpdatesListActivity {
                 appBar.setExpanded(false);
             }
         } else {
-            findViewById(R.id.refresh).setOnClickListener(new View.OnClickListener() {
-                @Override
-                public void onClick(View v) {
-                    downloadUpdatesList(true);
-                }
-            });
-            findViewById(R.id.preferences).setOnClickListener(new View.OnClickListener() {
-                @Override
-                public void onClick(View v) {
-                    showPreferencesDialog();
-                }
-            });
+            findViewById(R.id.refresh).setOnClickListener(v -> downloadUpdatesList(true));
+            findViewById(R.id.preferences).setOnClickListener(v -> showPreferencesDialog());
         }
     }
 
@@ -222,21 +214,18 @@ public class UpdatesActivity extends UpdatesListActivity {
 
     @Override
     public boolean onOptionsItemSelected(MenuItem item) {
-        switch (item.getItemId()) {
-            case R.id.menu_refresh: {
-                downloadUpdatesList(true);
-                return true;
-            }
-            case R.id.menu_preferences: {
-                showPreferencesDialog();
-                return true;
-            }
-            case R.id.menu_show_changelog: {
-                Intent openUrl = new Intent(Intent.ACTION_VIEW,
-                        Uri.parse(Utils.getChangelogURL(this)));
-                startActivity(openUrl);
-                return true;
-            }
+        int itemId = item.getItemId();
+        if (itemId == R.id.menu_refresh) {
+            downloadUpdatesList(true);
+            return true;
+        } else if (itemId == R.id.menu_preferences) {
+            showPreferencesDialog();
+            return true;
+        } else if (itemId == R.id.menu_show_changelog) {
+            Intent openUrl = new Intent(Intent.ACTION_VIEW,
+                    Uri.parse(Utils.getChangelogURL(this)));
+            startActivity(openUrl);
+            return true;
         }
         return super.onOptionsItemSelected(item);
     }
@@ -247,7 +236,7 @@ public class UpdatesActivity extends UpdatesListActivity {
         return true;
     }
 
-    private ServiceConnection mConnection = new ServiceConnection() {
+    private final ServiceConnection mConnection = new ServiceConnection() {
 
         @Override
         public void onServiceConnected(ComponentName className,
@@ -330,6 +319,7 @@ public class UpdatesActivity extends UpdatesListActivity {
             }
             // In case we set a one-shot check because of a previous failure
             UpdatesCheckReceiver.cancelUpdatesCheck(this);
+            //noinspection ResultOfMethodCallIgnored
             jsonNew.renameTo(json);
         } catch (IOException | JSONException e) {
             Log.e(TAG, "Could not read json", e);
@@ -356,12 +346,11 @@ public class UpdatesActivity extends UpdatesListActivity {
             }
 
             @Override
-            public void onResponse(int statusCode, String url,
-                    DownloadClient.Headers headers) {
+            public void onResponse(DownloadClient.Headers headers) {
             }
 
             @Override
-            public void onSuccess(File destination) {
+            public void onSuccess() {
                 runOnUiThread(() -> {
                     Log.d(TAG, "List downloaded");
                     processNewJson(jsonFile, jsonFileTmp, manualRefresh);
@@ -394,7 +383,7 @@ public class UpdatesActivity extends UpdatesListActivity {
         String lastCheckString = getString(R.string.header_last_updates_check,
                 StringGenerator.getDateLocalized(this, DateFormat.LONG, lastCheck),
                 StringGenerator.getTimeLocalized(this, lastCheck));
-        TextView headerLastCheck = (TextView) findViewById(R.id.header_last_check);
+        TextView headerLastCheck = findViewById(R.id.header_last_check);
         headerLastCheck.setText(lastCheckString);
     }
 
@@ -451,14 +440,14 @@ public class UpdatesActivity extends UpdatesListActivity {
         }
     }
 
+    @SuppressLint("ClickableViewAccessibility")
     private void showPreferencesDialog() {
         View view = LayoutInflater.from(this).inflate(R.layout.preferences_dialog, null);
-        Spinner autoCheckInterval =
-                view.findViewById(R.id.preferences_auto_updates_check_interval);
-        Switch autoDelete = view.findViewById(R.id.preferences_auto_delete_updates);
-        Switch dataWarning = view.findViewById(R.id.preferences_mobile_data_warning);
-        Switch abPerfMode = view.findViewById(R.id.preferences_ab_perf_mode);
-        Switch updateRecovery = view.findViewById(R.id.preferences_update_recovery);
+        Spinner autoCheckInterval = view.findViewById(R.id.preferences_auto_updates_check_interval);
+        SwitchCompat autoDelete = view.findViewById(R.id.preferences_auto_delete_updates);
+        SwitchCompat dataWarning = view.findViewById(R.id.preferences_mobile_data_warning);
+        SwitchCompat abPerfMode = view.findViewById(R.id.preferences_ab_perf_mode);
+        SwitchCompat updateRecovery = view.findViewById(R.id.preferences_update_recovery);
 
         if (!Utils.isABDevice()) {
             abPerfMode.setVisibility(View.GONE);
@@ -471,7 +460,7 @@ public class UpdatesActivity extends UpdatesListActivity {
         abPerfMode.setChecked(prefs.getBoolean(Constants.PREF_AB_PERF_MODE, false));
 
         if (getResources().getBoolean(R.bool.config_hideRecoveryUpdate)) {
-            // Hide the update feature if explicitely requested.
+            // Hide the update feature if explicitly requested.
             // Might be the case of A-only devices using prebuilt vendor images.
             updateRecovery.setVisibility(View.GONE);
         } else if (Utils.isRecoveryUpdateExecPresent()) {
@@ -505,12 +494,9 @@ public class UpdatesActivity extends UpdatesListActivity {
                     prefs.edit()
                             .putInt(Constants.PREF_AUTO_UPDATES_CHECK_INTERVAL,
                                     autoCheckInterval.getSelectedItemPosition())
-                            .putBoolean(Constants.PREF_AUTO_DELETE_UPDATES,
-                                    autoDelete.isChecked())
-                            .putBoolean(Constants.PREF_MOBILE_DATA_WARNING,
-                                    dataWarning.isChecked())
-                            .putBoolean(Constants.PREF_AB_PERF_MODE,
-                                    abPerfMode.isChecked())
+                            .putBoolean(Constants.PREF_AUTO_DELETE_UPDATES, autoDelete.isChecked())
+                            .putBoolean(Constants.PREF_MOBILE_DATA_WARNING, dataWarning.isChecked())
+                            .putBoolean(Constants.PREF_AB_PERF_MODE, abPerfMode.isChecked())
                             .apply();
 
                     if (Utils.isUpdateCheckEnabled(this)) {
diff --git a/src/org/lineageos/updater/UpdatesCheckReceiver.java b/src/org/lineageos/updater/UpdatesCheckReceiver.java
index 288cd1a3..e6c7677f 100644
--- a/src/org/lineageos/updater/UpdatesCheckReceiver.java
+++ b/src/org/lineageos/updater/UpdatesCheckReceiver.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2017 The LineageOS Project
+ * Copyright (C) 2017-2022 The LineageOS Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -84,17 +84,17 @@ public class UpdatesCheckReceiver extends BroadcastReceiver {
             }
 
             @Override
-            public void onResponse(int statusCode, String url,
-                    DownloadClient.Headers headers) {
+            public void onResponse(DownloadClient.Headers headers) {
             }
 
             @Override
-            public void onSuccess(File destination) {
+            public void onSuccess() {
                 try {
                     if (json.exists() && Utils.checkForNewUpdates(json, jsonNew)) {
                         showNotification(context);
                         updateRepeatingUpdatesCheck(context);
                     }
+                    //noinspection ResultOfMethodCallIgnored
                     jsonNew.renameTo(json);
                     long currentMillis = System.currentTimeMillis();
                     preferences.edit()
@@ -123,8 +123,8 @@ public class UpdatesCheckReceiver extends BroadcastReceiver {
     }
 
     private static void showNotification(Context context) {
-        NotificationManager notificationManager =
-                (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
+        NotificationManager notificationManager = context.getSystemService(
+                NotificationManager.class);
         NotificationChannel notificationChannel = new NotificationChannel(
                 NEW_UPDATES_NOTIFICATION_CHANNEL,
                 context.getString(R.string.new_updates_channel_title),
@@ -159,7 +159,7 @@ public class UpdatesCheckReceiver extends BroadcastReceiver {
         }
 
         PendingIntent updateCheckIntent = getRepeatingUpdatesCheckIntent(context);
-        AlarmManager alarmMgr = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
+        AlarmManager alarmMgr = context.getSystemService(AlarmManager.class);
         alarmMgr.setRepeating(AlarmManager.RTC, System.currentTimeMillis() +
                 Utils.getUpdateCheckInterval(context), Utils.getUpdateCheckInterval(context),
                 updateCheckIntent);
@@ -170,7 +170,7 @@ public class UpdatesCheckReceiver extends BroadcastReceiver {
     }
 
     public static void cancelRepeatingUpdatesCheck(Context context) {
-        AlarmManager alarmMgr = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
+        AlarmManager alarmMgr = context.getSystemService(AlarmManager.class);
         alarmMgr.cancel(getRepeatingUpdatesCheckIntent(context));
     }
 
@@ -183,7 +183,7 @@ public class UpdatesCheckReceiver extends BroadcastReceiver {
     public static void scheduleUpdatesCheck(Context context) {
         long millisToNextCheck = AlarmManager.INTERVAL_HOUR * 2;
         PendingIntent updateCheckIntent = getUpdatesCheckIntent(context);
-        AlarmManager alarmMgr = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
+        AlarmManager alarmMgr = context.getSystemService(AlarmManager.class);
         alarmMgr.set(AlarmManager.ELAPSED_REALTIME,
                 SystemClock.elapsedRealtime() + millisToNextCheck,
                 updateCheckIntent);
@@ -193,7 +193,7 @@ public class UpdatesCheckReceiver extends BroadcastReceiver {
     }
 
     public static void cancelUpdatesCheck(Context context) {
-        AlarmManager alarmMgr = (AlarmManager) context.getSystemService(Context.ALARM_SERVICE);
+        AlarmManager alarmMgr = context.getSystemService(AlarmManager.class);
         alarmMgr.cancel(getUpdatesCheckIntent(context));
         Log.d(TAG, "Cancelling pending one-shot check");
     }
diff --git a/src/org/lineageos/updater/UpdatesDbHelper.java b/src/org/lineageos/updater/UpdatesDbHelper.java
index 71a20758..6c11a60c 100644
--- a/src/org/lineageos/updater/UpdatesDbHelper.java
+++ b/src/org/lineageos/updater/UpdatesDbHelper.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2017 The LineageOS Project
+ * Copyright (C) 2017-2022 The LineageOS Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -75,18 +75,11 @@ public class UpdatesDbHelper extends SQLiteOpenHelper {
         onUpgrade(db, oldVersion, newVersion);
     }
 
-    public long addUpdate(Update update) {
+    public void addUpdateWithOnConflict(Update update, int conflictAlgorithm) {
         SQLiteDatabase db = getWritableDatabase();
         ContentValues values = new ContentValues();
         fillContentValues(update, values);
-        return db.insert(UpdateEntry.TABLE_NAME, null, values);
-    }
-
-    public long addUpdateWithOnConflict(Update update, int conflictAlgorithm) {
-        SQLiteDatabase db = getWritableDatabase();
-        ContentValues values = new ContentValues();
-        fillContentValues(update, values);
-        return db.insertWithOnConflict(UpdateEntry.TABLE_NAME, null, values, conflictAlgorithm);
+        db.insertWithOnConflict(UpdateEntry.TABLE_NAME, null, values, conflictAlgorithm);
     }
 
     private static void fillContentValues(Update update, ContentValues values) {
@@ -99,52 +92,25 @@ public class UpdatesDbHelper extends SQLiteOpenHelper {
         values.put(UpdateEntry.COLUMN_NAME_SIZE, update.getFileSize());
     }
 
-    public boolean removeUpdate(String downloadId) {
+    public void removeUpdate(String downloadId) {
         SQLiteDatabase db = getWritableDatabase();
         String selection = UpdateEntry.COLUMN_NAME_DOWNLOAD_ID + " = ?";
         String[] selectionArgs = {downloadId};
-        return db.delete(UpdateEntry.TABLE_NAME, selection, selectionArgs) != 0;
+        db.delete(UpdateEntry.TABLE_NAME, selection, selectionArgs);
     }
 
-    public boolean removeUpdate(long rowId) {
-        SQLiteDatabase db = getWritableDatabase();
-        String selection = UpdateEntry._ID + " = " + rowId;
-        return db.delete(UpdateEntry.TABLE_NAME, selection, null) != 0;
-    }
-
-    public boolean changeUpdateStatus(Update update) {
+    public void changeUpdateStatus(Update update) {
         String selection = UpdateEntry.COLUMN_NAME_DOWNLOAD_ID + " = ?";
         String[] selectionArgs = {update.getDownloadId()};
-        return changeUpdateStatus(selection, selectionArgs, update.getPersistentStatus());
+        changeUpdateStatus(selection, selectionArgs, update.getPersistentStatus());
     }
 
-    public boolean changeUpdateStatus(long rowId, int status) {
-        String selection = UpdateEntry._ID + " = " + rowId;
-        return changeUpdateStatus(selection, null, status);
-    }
-
-    private boolean changeUpdateStatus(String selection, String[] selectionArgs,
-            int status) {
+    private void changeUpdateStatus(String selection, String[] selectionArgs,
+                                    int status) {
         SQLiteDatabase db = getWritableDatabase();
         ContentValues values = new ContentValues();
         values.put(UpdateEntry.COLUMN_NAME_STATUS, status);
-        return db.update(UpdateEntry.TABLE_NAME, values, selection, selectionArgs) != 0;
-    }
-
-    public Update getUpdate(long rowId) {
-        String selection = UpdateEntry._ID + " = " + rowId;
-        return getUpdate(selection, null);
-    }
-
-    public Update getUpdate(String downloadId) {
-        String selection = UpdateEntry.COLUMN_NAME_DOWNLOAD_ID + " = ?";
-        String[] selectionArgs = {downloadId};
-        return getUpdate(selection, selectionArgs);
-    }
-
-    private Update getUpdate(String selection, String[] selectionArgs) {
-        List<Update> updates = getUpdates(selection, selectionArgs);
-        return updates != null ? updates.get(0) : null;
+        db.update(UpdateEntry.TABLE_NAME, values, selection, selectionArgs);
     }
 
     public List<Update> getUpdates() {
diff --git a/src/org/lineageos/updater/UpdatesListAdapter.java b/src/org/lineageos/updater/UpdatesListAdapter.java
index 44474ac4..53bd29e9 100644
--- a/src/org/lineageos/updater/UpdatesListAdapter.java
+++ b/src/org/lineageos/updater/UpdatesListAdapter.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2017 The LineageOS Project
+ * Copyright (C) 2017-2022 The LineageOS Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -15,7 +15,6 @@
  */
 package org.lineageos.updater;
 
-import android.content.Context;
 import android.content.Intent;
 import android.content.IntentFilter;
 import android.content.SharedPreferences;
@@ -39,6 +38,7 @@ import android.widget.ImageButton;
 import android.widget.ProgressBar;
 import android.widget.TextView;
 
+import androidx.annotation.NonNull;
 import androidx.appcompat.app.AlertDialog;
 import androidx.appcompat.view.ContextThemeWrapper;
 import androidx.appcompat.view.menu.MenuBuilder;
@@ -77,7 +77,7 @@ public class UpdatesListAdapter extends RecyclerView.Adapter<UpdatesListAdapter.
     private List<String> mDownloadIds;
     private String mSelectedDownload;
     private UpdaterController mUpdaterController;
-    private UpdatesListActivity mActivity;
+    private final UpdatesListActivity mActivity;
 
     private AlertDialog infoDialog;
 
@@ -93,27 +93,27 @@ public class UpdatesListAdapter extends RecyclerView.Adapter<UpdatesListAdapter.
     }
 
     public static class ViewHolder extends RecyclerView.ViewHolder {
-        private Button mAction;
-        private ImageButton mMenu;
+        private final Button mAction;
+        private final ImageButton mMenu;
 
-        private TextView mBuildDate;
-        private TextView mBuildVersion;
-        private TextView mBuildSize;
+        private final TextView mBuildDate;
+        private final TextView mBuildVersion;
+        private final TextView mBuildSize;
 
-        private ProgressBar mProgressBar;
-        private TextView mProgressText;
+        private final ProgressBar mProgressBar;
+        private final TextView mProgressText;
 
         public ViewHolder(final View view) {
             super(view);
-            mAction = (Button) view.findViewById(R.id.update_action);
-            mMenu = (ImageButton) view.findViewById(R.id.update_menu);
+            mAction = view.findViewById(R.id.update_action);
+            mMenu = view.findViewById(R.id.update_menu);
 
-            mBuildDate = (TextView) view.findViewById(R.id.build_date);
-            mBuildVersion = (TextView) view.findViewById(R.id.build_version);
-            mBuildSize = (TextView) view.findViewById(R.id.build_size);
+            mBuildDate = view.findViewById(R.id.build_date);
+            mBuildVersion = view.findViewById(R.id.build_version);
+            mBuildSize = view.findViewById(R.id.build_size);
 
-            mProgressBar = (ProgressBar) view.findViewById(R.id.progress_bar);
-            mProgressText = (TextView) view.findViewById(R.id.progress_text);
+            mProgressBar = view.findViewById(R.id.progress_bar);
+            mProgressText = view.findViewById(R.id.progress_text);
         }
     }
 
@@ -125,6 +125,7 @@ public class UpdatesListAdapter extends RecyclerView.Adapter<UpdatesListAdapter.
         mAlphaDisabledValue = tv.getFloat();
     }
 
+    @NonNull
     @Override
     public ViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
         View view = LayoutInflater.from(viewGroup.getContext())
@@ -133,7 +134,7 @@ public class UpdatesListAdapter extends RecyclerView.Adapter<UpdatesListAdapter.
     }
 
     @Override
-    public void onViewDetachedFromWindow(ViewHolder holder) {
+    public void onViewDetachedFromWindow(@NonNull ViewHolder holder) {
         super.onViewDetachedFromWindow(holder);
 
         if (infoDialog != null) {
@@ -191,8 +192,8 @@ public class UpdatesListAdapter extends RecyclerView.Adapter<UpdatesListAdapter.
             String total = Formatter.formatShortFileSize(mActivity, update.getFileSize());
             String percentage = NumberFormat.getPercentInstance().format(
                     update.getProgress() / 100.f);
-            viewHolder.mProgressText.setText(mActivity.getString(R.string.list_download_progress_new,
-                    downloaded, total, percentage));
+            viewHolder.mProgressText.setText(mActivity.getString(
+                    R.string.list_download_progress_new, downloaded, total, percentage));
             viewHolder.mProgressBar.setIndeterminate(false);
             viewHolder.mProgressBar.setProgress(update.getProgress());
         }
@@ -229,7 +230,7 @@ public class UpdatesListAdapter extends RecyclerView.Adapter<UpdatesListAdapter.
     }
 
     @Override
-    public void onBindViewHolder(final ViewHolder viewHolder, int i) {
+    public void onBindViewHolder(@NonNull final ViewHolder viewHolder, int i) {
         if (mDownloadIds == null) {
             viewHolder.mAction.setEnabled(false);
             return;
@@ -311,7 +312,7 @@ public class UpdatesListAdapter extends RecyclerView.Adapter<UpdatesListAdapter.
         }
 
         View checkboxView = LayoutInflater.from(mActivity).inflate(R.layout.checkbox_view, null);
-        CheckBox checkbox = (CheckBox) checkboxView.findViewById(R.id.checkbox);
+        CheckBox checkbox = checkboxView.findViewById(R.id.checkbox);
         checkbox.setText(R.string.checkbox_mobile_data_warning);
 
         new AlertDialog.Builder(mActivity)
@@ -370,7 +371,10 @@ public class UpdatesListAdapter extends RecyclerView.Adapter<UpdatesListAdapter.
                 final boolean canInstall = Utils.canInstall(update);
                 clickListener = enabled ? view -> {
                     if (canInstall) {
-                        getInstallDialog(downloadId).show();
+                        AlertDialog.Builder installDialog = getInstallDialog(downloadId);
+                        if (installDialog != null) {
+                            installDialog.show();
+                        }
                     } else {
                         mActivity.showSnackbar(R.string.snack_update_not_installable,
                                 Snackbar.LENGTH_LONG);
@@ -400,8 +404,7 @@ public class UpdatesListAdapter extends RecyclerView.Adapter<UpdatesListAdapter.
                 button.setText(R.string.reboot);
                 button.setEnabled(enabled);
                 clickListener = enabled ? view -> {
-                    PowerManager pm =
-                            (PowerManager) mActivity.getSystemService(Context.POWER_SERVICE);
+                    PowerManager pm = mActivity.getSystemService(PowerManager.class);
                     pm.reboot(null);
                 } : null;
             }
@@ -438,9 +441,7 @@ public class UpdatesListAdapter extends RecyclerView.Adapter<UpdatesListAdapter.
 
     private View.OnClickListener getClickListener(final UpdateInfo update,
             final boolean canDelete, View anchor) {
-        return view -> {
-            startActionMode(update, canDelete, anchor);
-        };
+        return view -> startActionMode(update, canDelete, anchor);
     }
 
     private AlertDialog.Builder getInstallDialog(final String downloadId) {
@@ -509,24 +510,24 @@ public class UpdatesListAdapter extends RecyclerView.Adapter<UpdatesListAdapter.
                 update.getPersistentStatus() == UpdateStatus.Persistent.VERIFIED);
 
         popupMenu.setOnMenuItemClickListener(item -> {
-            switch (item.getItemId()) {
-                case R.id.menu_delete_action:
-                    getDeleteDialog(update.getDownloadId()).show();
-                    return true;
-                case R.id.menu_copy_url:
-                    Utils.addToClipboard(mActivity,
-                            mActivity.getString(R.string.label_download_url),
-                            update.getDownloadUrl(),
-                            mActivity.getString(R.string.toast_download_url_copied));
-                    return true;
-                case R.id.menu_export_update:
-                    // TODO: start exporting once the permission has been granted
-                    boolean hasPermission = PermissionsUtils.checkAndRequestStoragePermission(
-                            mActivity, 0);
-                    if (hasPermission) {
-                        exportUpdate(update);
-                    }
-                    return true;
+            int itemId = item.getItemId();
+            if (itemId == R.id.menu_delete_action) {
+                getDeleteDialog(update.getDownloadId()).show();
+                return true;
+            } else if (itemId == R.id.menu_copy_url) {
+                Utils.addToClipboard(mActivity,
+                        mActivity.getString(R.string.label_download_url),
+                        update.getDownloadUrl(),
+                        mActivity.getString(R.string.toast_download_url_copied));
+                return true;
+            } else if (itemId == R.id.menu_export_update) {
+                // TODO: start exporting once the permission has been granted
+                boolean hasPermission = PermissionsUtils.checkAndRequestStoragePermission(
+                        mActivity, 0);
+                if (hasPermission) {
+                    exportUpdate(update);
+                }
+                return true;
             }
             return false;
         });
@@ -561,8 +562,10 @@ public class UpdatesListAdapter extends RecyclerView.Adapter<UpdatesListAdapter.
                 .setPositiveButton(android.R.string.ok, null)
                 .setMessage(message)
                 .show();
-        TextView textView = (TextView) infoDialog.findViewById(android.R.id.message);
-        textView.setMovementMethod(LinkMovementMethod.getInstance());
+        TextView textView = infoDialog.findViewById(android.R.id.message);
+        if (textView != null) {
+            textView.setMovementMethod(LinkMovementMethod.getInstance());
+        }
     }
 
     private boolean isBatteryLevelOk() {
diff --git a/src/org/lineageos/updater/controller/ABUpdateInstaller.java b/src/org/lineageos/updater/controller/ABUpdateInstaller.java
index a4597c0e..9fdc75e0 100644
--- a/src/org/lineageos/updater/controller/ABUpdateInstaller.java
+++ b/src/org/lineageos/updater/controller/ABUpdateInstaller.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2017 The LineageOS Project
+ * Copyright (C) 2017-2022 The LineageOS Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -52,7 +52,7 @@ class ABUpdateInstaller {
     private final Context mContext;
     private String mDownloadId;
 
-    private UpdateEngine mUpdateEngine;
+    private final UpdateEngine mUpdateEngine;
     private boolean mBound;
 
     private boolean mFinalizing;
@@ -130,11 +130,6 @@ class ABUpdateInstaller {
         return pref.getString(ABUpdateInstaller.PREF_INSTALLING_SUSPENDED_AB_ID, null) != null;
     }
 
-    static synchronized boolean isInstallingUpdateSuspended(Context context, String downloadId) {
-        SharedPreferences pref = PreferenceManager.getDefaultSharedPreferences(context);
-        return downloadId.equals(pref.getString(ABUpdateInstaller.PREF_INSTALLING_SUSPENDED_AB_ID, null));
-    }
-
     static synchronized boolean isWaitingForReboot(Context context, String downloadId) {
         String waitingId = PreferenceManager.getDefaultSharedPreferences(context)
                 .getString(Constants.PREF_NEEDS_REBOOT_ID, null);
@@ -155,10 +150,10 @@ class ABUpdateInstaller {
         return sInstance;
     }
 
-    public boolean install(String downloadId) {
+    public void install(String downloadId) {
         if (isInstallingUpdate(mContext)) {
             Log.e(TAG, "Already installing an update");
-            return false;
+            return;
         }
 
         mDownloadId = downloadId;
@@ -169,7 +164,7 @@ class ABUpdateInstaller {
             mUpdaterController.getActualUpdate(downloadId)
                     .setStatus(UpdateStatus.INSTALLATION_FAILED);
             mUpdaterController.notifyUpdateChange(downloadId);
-            return false;
+            return;
         }
 
         long offset;
@@ -194,7 +189,7 @@ class ABUpdateInstaller {
             mUpdaterController.getActualUpdate(mDownloadId)
                     .setStatus(UpdateStatus.INSTALLATION_FAILED);
             mUpdaterController.notifyUpdateChange(mDownloadId);
-            return false;
+            return;
         }
 
         if (!mBound) {
@@ -204,7 +199,7 @@ class ABUpdateInstaller {
                 mUpdaterController.getActualUpdate(downloadId)
                         .setStatus(UpdateStatus.INSTALLATION_FAILED);
                 mUpdaterController.notifyUpdateChange(downloadId);
-                return false;
+                return;
             }
         }
 
@@ -222,17 +217,16 @@ class ABUpdateInstaller {
                 .putString(PREF_INSTALLING_AB_ID, mDownloadId)
                 .apply();
 
-        return true;
     }
 
-    public boolean reconnect() {
+    public void reconnect() {
         if (!isInstallingUpdate(mContext)) {
             Log.e(TAG, "reconnect: Not installing any update");
-            return false;
+            return;
         }
 
         if (mBound) {
-            return true;
+            return;
         }
 
         mDownloadId = PreferenceManager.getDefaultSharedPreferences(mContext)
@@ -242,10 +236,8 @@ class ABUpdateInstaller {
         mBound = mUpdateEngine.bind(mUpdateEngineCallback);
         if (!mBound) {
             Log.e(TAG, "Could not bind");
-            return false;
         }
 
-        return true;
     }
 
     private void installationDone(boolean needsReboot) {
@@ -257,15 +249,15 @@ class ABUpdateInstaller {
                 .apply();
     }
 
-    public boolean cancel() {
+    public void cancel() {
         if (!isInstallingUpdate(mContext)) {
             Log.e(TAG, "cancel: Not installing any update");
-            return false;
+            return;
         }
 
         if (!mBound) {
             Log.e(TAG, "Not connected to update engine");
-            return false;
+            return;
         }
 
         mUpdateEngine.cancel();
@@ -275,22 +267,21 @@ class ABUpdateInstaller {
                 .setStatus(UpdateStatus.INSTALLATION_CANCELLED);
         mUpdaterController.notifyUpdateChange(mDownloadId);
 
-        return true;
     }
 
     public void setPerformanceMode(boolean enable) {
         mUpdateEngine.setPerformanceMode(enable);
     }
 
-    public boolean suspend() {
+    public void suspend() {
         if (!isInstallingUpdate(mContext)) {
             Log.e(TAG, "cancel: Not installing any update");
-            return false;
+            return;
         }
 
         if (!mBound) {
             Log.e(TAG, "Not connected to update engine");
-            return false;
+            return;
         }
 
         mUpdateEngine.suspend();
@@ -303,18 +294,17 @@ class ABUpdateInstaller {
                 .putString(PREF_INSTALLING_SUSPENDED_AB_ID, mDownloadId)
                 .apply();
 
-        return true;
     }
 
-    public boolean resume() {
+    public void resume() {
         if (!isInstallingUpdateSuspended(mContext)) {
             Log.e(TAG, "cancel: No update is suspended");
-            return false;
+            return;
         }
 
         if (!mBound) {
             Log.e(TAG, "Not connected to update engine");
-            return false;
+            return;
         }
 
         mUpdateEngine.resume();
@@ -329,6 +319,5 @@ class ABUpdateInstaller {
                 .remove(PREF_INSTALLING_SUSPENDED_AB_ID)
                 .apply();
 
-        return true;
     }
 }
diff --git a/src/org/lineageos/updater/controller/UpdateInstaller.java b/src/org/lineageos/updater/controller/UpdateInstaller.java
index 1be4ec35..9735429c 100644
--- a/src/org/lineageos/updater/controller/UpdateInstaller.java
+++ b/src/org/lineageos/updater/controller/UpdateInstaller.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2017 The LineageOS Project
+ * Copyright (C) 2017-2022 The LineageOS Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -113,7 +113,7 @@ class UpdateInstaller {
         Runnable copyUpdateRunnable = new Runnable() {
             private long mLastUpdate = -1;
 
-            FileUtils.ProgressCallBack mProgressCallBack = new FileUtils.ProgressCallBack() {
+            final FileUtils.ProgressCallBack mProgressCallBack = new FileUtils.ProgressCallBack() {
                 @Override
                 public void update(int progress) {
                     long now = SystemClock.elapsedRealtime();
@@ -137,12 +137,14 @@ class UpdateInstaller {
                                 .setStatus(UpdateStatus.INSTALLATION_CANCELLED);
                         mUpdaterController.getActualUpdate(update.getDownloadId())
                                 .setInstallProgress(0);
+                        //noinspection ResultOfMethodCallIgnored
                         uncryptFile.delete();
                     } else {
                         installPackage(uncryptFile, update.getDownloadId());
                     }
                 } catch (IOException e) {
                     Log.e(TAG, "Could not copy update", e);
+                    //noinspection ResultOfMethodCallIgnored
                     uncryptFile.delete();
                     mUpdaterController.getActualUpdate(update.getDownloadId())
                             .setStatus(UpdateStatus.INSTALLATION_FAILED);
diff --git a/src/org/lineageos/updater/controller/UpdaterController.java b/src/org/lineageos/updater/controller/UpdaterController.java
index 62f8ca7d..5d7d51a7 100644
--- a/src/org/lineageos/updater/controller/UpdaterController.java
+++ b/src/org/lineageos/updater/controller/UpdaterController.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2017 The LineageOS Project
+ * Copyright (C) 2017-2022 The LineageOS Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -15,6 +15,7 @@
  */
 package org.lineageos.updater.controller;
 
+import android.annotation.SuppressLint;
 import android.content.Context;
 import android.content.Intent;
 import android.database.sqlite.SQLiteDatabase;
@@ -63,11 +64,7 @@ public class UpdaterController {
     private final File mDownloadRoot;
 
     private int mActiveDownloads = 0;
-    private Set<String> mVerifyingUpdates = new HashSet<>();
-
-    public static synchronized UpdaterController getInstance() {
-        return sUpdaterController;
-    }
+    private final Set<String> mVerifyingUpdates = new HashSet<>();
 
     protected static synchronized UpdaterController getInstance(Context context) {
         if (sUpdaterController == null) {
@@ -80,8 +77,8 @@ public class UpdaterController {
         mBroadcastManager = LocalBroadcastManager.getInstance(context);
         mUpdatesDbHelper = new UpdatesDbHelper(context);
         mDownloadRoot = Utils.getDownloadPath(context);
-        PowerManager powerManager = (PowerManager) context.getSystemService(Context.POWER_SERVICE);
-        mWakeLock = powerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "Updater");
+        PowerManager powerManager = context.getSystemService(PowerManager.class);
+        mWakeLock = powerManager.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, "Updater:wakelock");
         mWakeLock.setReferenceCounted(false);
         mContext = context.getApplicationContext();
 
@@ -92,7 +89,7 @@ public class UpdaterController {
         }
     }
 
-    private class DownloadEntry {
+    private static class DownloadEntry {
         final Update mUpdate;
         DownloadClient mDownloadClient;
         private DownloadEntry(Update update) {
@@ -100,7 +97,7 @@ public class UpdaterController {
         }
     }
 
-    private Map<String, DownloadEntry> mDownloads = new HashMap<>();
+    private final Map<String, DownloadEntry> mDownloads = new HashMap<>();
 
     void notifyUpdateChange(String downloadId) {
         Intent intent = new Intent();
@@ -156,8 +153,12 @@ public class UpdaterController {
         return new DownloadClient.DownloadCallback() {
 
             @Override
-            public void onResponse(int statusCode, String url, DownloadClient.Headers headers) {
-                final Update update = mDownloads.get(downloadId).mUpdate;
+            public void onResponse(DownloadClient.Headers headers) {
+                final DownloadEntry entry = mDownloads.get(downloadId);
+                if (entry == null) {
+                    return;
+                }
+                final Update update = entry.mUpdate;
                 String contentLength = headers.get("Content-Length");
                 if (contentLength != null) {
                     try {
@@ -177,27 +178,33 @@ public class UpdaterController {
             }
 
             @Override
-            public void onSuccess(File destination) {
+            public void onSuccess() {
                 Log.d(TAG, "Download complete");
-                Update update = mDownloads.get(downloadId).mUpdate;
-                update.setStatus(UpdateStatus.VERIFYING);
-                removeDownloadClient(mDownloads.get(downloadId));
-                verifyUpdateAsync(downloadId);
-                notifyUpdateChange(downloadId);
-                tryReleaseWakelock();
+                DownloadEntry entry = mDownloads.get(downloadId);
+                if (entry != null) {
+                    Update update = entry.mUpdate;
+                    update.setStatus(UpdateStatus.VERIFYING);
+                    removeDownloadClient(entry);
+                    verifyUpdateAsync(downloadId);
+                    notifyUpdateChange(downloadId);
+                    tryReleaseWakelock();
+                }
             }
 
             @Override
             public void onFailure(boolean cancelled) {
-                Update update = mDownloads.get(downloadId).mUpdate;
                 if (cancelled) {
                     Log.d(TAG, "Download cancelled");
                     // Already notified
                 } else {
-                    Log.e(TAG, "Download failed");
-                    removeDownloadClient(mDownloads.get(downloadId));
-                    update.setStatus(UpdateStatus.PAUSED_ERROR);
-                    notifyUpdateChange(downloadId);
+                    DownloadEntry entry = mDownloads.get(downloadId);
+                    if (entry != null) {
+                        Update update = entry.mUpdate;
+                        Log.e(TAG, "Download failed");
+                        removeDownloadClient(entry);
+                        update.setStatus(UpdateStatus.PAUSED_ERROR);
+                        notifyUpdateChange(downloadId);
+                    }
                 }
                 tryReleaseWakelock();
             }
@@ -210,9 +217,12 @@ public class UpdaterController {
             private int mProgress = 0;
 
             @Override
-            public void update(long bytesRead, long contentLength, long speed, long eta,
-                    boolean done) {
-                Update update = mDownloads.get(downloadId).mUpdate;
+            public void update(long bytesRead, long contentLength, long speed, long eta) {
+                DownloadEntry entry = mDownloads.get(downloadId);
+                if (entry == null) {
+                    return;
+                }
+                Update update = entry.mUpdate;
                 if (contentLength <= 0) {
                     if (update.getFileSize() <= 0) {
                         return;
@@ -224,7 +234,7 @@ public class UpdaterController {
                     return;
                 }
                 final long now = SystemClock.elapsedRealtime();
-                int progress = Math.round(bytesRead * 100 / contentLength);
+                int progress = Math.round(bytesRead * 100f / contentLength);
                 if (progress != mProgress || mLastUpdate - now > MAX_REPORT_INTERVAL_MS) {
                     mProgress = progress;
                     mLastUpdate = now;
@@ -237,24 +247,29 @@ public class UpdaterController {
         };
     }
 
+    @SuppressLint("SetWorldReadable")
     private void verifyUpdateAsync(final String downloadId) {
         mVerifyingUpdates.add(downloadId);
         new Thread(() -> {
-            Update update = mDownloads.get(downloadId).mUpdate;
-            File file = update.getFile();
-            if (file.exists() && verifyPackage(file)) {
-                file.setReadable(true, false);
-                update.setPersistentStatus(UpdateStatus.Persistent.VERIFIED);
-                mUpdatesDbHelper.changeUpdateStatus(update);
-                update.setStatus(UpdateStatus.VERIFIED);
-            } else {
-                update.setPersistentStatus(UpdateStatus.Persistent.UNKNOWN);
-                mUpdatesDbHelper.removeUpdate(downloadId);
-                update.setProgress(0);
-                update.setStatus(UpdateStatus.VERIFICATION_FAILED);
+            DownloadEntry entry = mDownloads.get(downloadId);
+            if (entry != null) {
+                Update update = entry.mUpdate;
+                File file = update.getFile();
+                if (file.exists() && verifyPackage(file)) {
+                    //noinspection ResultOfMethodCallIgnored
+                    file.setReadable(true, false);
+                    update.setPersistentStatus(UpdateStatus.Persistent.VERIFIED);
+                    mUpdatesDbHelper.changeUpdateStatus(update);
+                    update.setStatus(UpdateStatus.VERIFIED);
+                } else {
+                    update.setPersistentStatus(UpdateStatus.Persistent.UNKNOWN);
+                    mUpdatesDbHelper.removeUpdate(downloadId);
+                    update.setProgress(0);
+                    update.setStatus(UpdateStatus.VERIFICATION_FAILED);
+                }
+                mVerifyingUpdates.remove(downloadId);
+                notifyUpdateChange(downloadId);
             }
-            mVerifyingUpdates.remove(downloadId);
-            notifyUpdateChange(downloadId);
         }).start();
     }
 
@@ -266,6 +281,7 @@ public class UpdaterController {
         } catch (Exception e) {
             Log.e(TAG, "Verification failed", e);
             if (file.exists()) {
+                //noinspection ResultOfMethodCallIgnored
                 file.delete();
             } else {
                 // The download was probably stopped. Exit silently
@@ -285,7 +301,7 @@ public class UpdaterController {
                 } else if (update.getFileSize() > 0) {
                     update.setStatus(UpdateStatus.PAUSED);
                     int progress = Math.round(
-                            update.getFile().length() * 100 / update.getFileSize());
+                            update.getFile().length() * 100f / update.getFileSize());
                     update.setProgress(progress);
                 }
                 break;
@@ -293,15 +309,6 @@ public class UpdaterController {
         return true;
     }
 
-    public void setUpdatesNotAvailableOnline(List<String> downloadIds) {
-        for (String downloadId : downloadIds) {
-            DownloadEntry update = mDownloads.get(downloadId);
-            if (update != null) {
-                update.mUpdate.setAvailableOnline(false);
-            }
-        }
-    }
-
     public void setUpdatesAvailableOnline(List<String> downloadIds, boolean purgeList) {
         List<String> toRemove = new ArrayList<>();
         for (DownloadEntry entry : mDownloads.values()) {
@@ -327,9 +334,12 @@ public class UpdaterController {
         Log.d(TAG, "Adding download: " + updateInfo.getDownloadId());
         if (mDownloads.containsKey(updateInfo.getDownloadId())) {
             Log.d(TAG, "Download (" + updateInfo.getDownloadId() + ") already added");
-            Update updateAdded = mDownloads.get(updateInfo.getDownloadId()).mUpdate;
-            updateAdded.setAvailableOnline(availableOnline && updateAdded.getAvailableOnline());
-            updateAdded.setDownloadUrl(updateInfo.getDownloadUrl());
+            DownloadEntry entry = mDownloads.get(updateInfo.getDownloadId());
+            if (entry != null) {
+                Update updateAdded = entry.mUpdate;
+                updateAdded.setAvailableOnline(availableOnline && updateAdded.getAvailableOnline());
+                updateAdded.setDownloadUrl(updateInfo.getDownloadUrl());
+            }
             return false;
         }
         Update update = new Update(updateInfo);
@@ -344,12 +354,18 @@ public class UpdaterController {
         return true;
     }
 
-    public boolean startDownload(String downloadId) {
+    @SuppressLint("WakelockTimeout")
+    public void startDownload(String downloadId) {
         Log.d(TAG, "Starting " + downloadId);
         if (!mDownloads.containsKey(downloadId) || isDownloading(downloadId)) {
-            return false;
+            return;
         }
-        Update update = mDownloads.get(downloadId).mUpdate;
+        DownloadEntry entry = mDownloads.get(downloadId);
+        if (entry == null) {
+            Log.e(TAG, "Could not get download entry");
+            return;
+        }
+        Update update = entry.mUpdate;
         File destination = new File(mDownloadRoot, update.getName());
         if (destination.exists()) {
             destination = Utils.appendSequentialNumber(destination);
@@ -369,28 +385,33 @@ public class UpdaterController {
             Log.e(TAG, "Could not build download client");
             update.setStatus(UpdateStatus.PAUSED_ERROR);
             notifyUpdateChange(downloadId);
-            return false;
+            return;
         }
-        addDownloadClient(mDownloads.get(downloadId), downloadClient);
+        addDownloadClient(entry, downloadClient);
         update.setStatus(UpdateStatus.STARTING);
         notifyUpdateChange(downloadId);
         downloadClient.start();
         mWakeLock.acquire();
-        return true;
     }
 
-    public boolean resumeDownload(String downloadId) {
+    @SuppressLint("WakelockTimeout")
+    public void resumeDownload(String downloadId) {
         Log.d(TAG, "Resuming " + downloadId);
         if (!mDownloads.containsKey(downloadId) || isDownloading(downloadId)) {
-            return false;
+            return;
         }
-        Update update = mDownloads.get(downloadId).mUpdate;
+        DownloadEntry entry = mDownloads.get(downloadId);
+        if (entry == null) {
+            Log.e(TAG, "Could not get download entry");
+            return;
+        }
+        Update update = entry.mUpdate;
         File file = update.getFile();
         if (file == null || !file.exists()) {
             Log.e(TAG, "The destination file of " + downloadId + " doesn't exist, can't resume");
             update.setStatus(UpdateStatus.PAUSED_ERROR);
             notifyUpdateChange(downloadId);
-            return false;
+            return;
         }
         if (file.exists() && update.getFileSize() > 0 && file.length() >= update.getFileSize()) {
             Log.d(TAG, "File already downloaded, starting verification");
@@ -411,31 +432,31 @@ public class UpdaterController {
                 Log.e(TAG, "Could not build download client");
                 update.setStatus(UpdateStatus.PAUSED_ERROR);
                 notifyUpdateChange(downloadId);
-                return false;
+                return;
             }
-            addDownloadClient(mDownloads.get(downloadId), downloadClient);
+            addDownloadClient(entry, downloadClient);
             update.setStatus(UpdateStatus.STARTING);
             notifyUpdateChange(downloadId);
             downloadClient.resume();
             mWakeLock.acquire();
         }
-        return true;
     }
 
-    public boolean pauseDownload(String downloadId) {
+    public void pauseDownload(String downloadId) {
         Log.d(TAG, "Pausing " + downloadId);
         if (!isDownloading(downloadId)) {
-            return false;
+            return;
         }
 
         DownloadEntry entry = mDownloads.get(downloadId);
-        entry.mDownloadClient.cancel();
-        removeDownloadClient(entry);
-        entry.mUpdate.setStatus(UpdateStatus.PAUSED);
-        entry.mUpdate.setEta(0);
-        entry.mUpdate.setSpeed(0);
-        notifyUpdateChange(downloadId);
-        return true;
+        if (entry != null) {
+            entry.mDownloadClient.cancel();
+            removeDownloadClient(entry);
+            entry.mUpdate.setStatus(UpdateStatus.PAUSED);
+            entry.mUpdate.setEta(0);
+            entry.mUpdate.setSpeed(0);
+            notifyUpdateChange(downloadId);
+        }
     }
 
     private void deleteUpdateAsync(final Update update) {
@@ -448,30 +469,27 @@ public class UpdaterController {
         }).start();
     }
 
-    public boolean deleteUpdate(String downloadId) {
+    public void deleteUpdate(String downloadId) {
         Log.d(TAG, "Cancelling " + downloadId);
         if (!mDownloads.containsKey(downloadId) || isDownloading(downloadId)) {
-            return false;
+            return;
         }
-        Update update = mDownloads.get(downloadId).mUpdate;
-        update.setStatus(UpdateStatus.DELETED);
-        update.setProgress(0);
-        update.setPersistentStatus(UpdateStatus.Persistent.UNKNOWN);
-        deleteUpdateAsync(update);
+        DownloadEntry entry = mDownloads.get(downloadId);
+        if (entry != null) {
+            Update update = entry.mUpdate;
+            update.setStatus(UpdateStatus.DELETED);
+            update.setProgress(0);
+            update.setPersistentStatus(UpdateStatus.Persistent.UNKNOWN);
+            deleteUpdateAsync(update);
 
-        if (!update.getAvailableOnline()) {
-            Log.d(TAG, "Download no longer available online, removing");
-            mDownloads.remove(downloadId);
-            notifyUpdateDelete(downloadId);
-        } else {
-            notifyUpdateChange(downloadId);
+            if (!update.getAvailableOnline()) {
+                Log.d(TAG, "Download no longer available online, removing");
+                mDownloads.remove(downloadId);
+                notifyUpdateDelete(downloadId);
+            } else {
+                notifyUpdateChange(downloadId);
+            }
         }
-
-        return true;
-    }
-
-    public Set<String> getIds() {
-        return mDownloads.keySet();
     }
 
     public List<UpdateInfo> getUpdates() {
@@ -493,6 +511,7 @@ public class UpdaterController {
     }
 
     public boolean isDownloading(String downloadId) {
+        //noinspection ConstantConditions
         return mDownloads.containsKey(downloadId) &&
                 mDownloads.get(downloadId).mDownloadClient != null;
     }
diff --git a/src/org/lineageos/updater/controller/UpdaterService.java b/src/org/lineageos/updater/controller/UpdaterService.java
index 33716180..14524430 100644
--- a/src/org/lineageos/updater/controller/UpdaterService.java
+++ b/src/org/lineageos/updater/controller/UpdaterService.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2017 The LineageOS Project
+ * Copyright (C) 2017-2022 The LineageOS Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -85,7 +85,7 @@ public class UpdaterService extends Service {
 
         mUpdaterController = UpdaterController.getInstance(this);
 
-        mNotificationManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
+        mNotificationManager = getSystemService(NotificationManager.class);
         NotificationChannel notificationChannel = new NotificationChannel(
                 ONGOING_NOTIFICATION_CHANNEL,
                 getString(R.string.ongoing_channel_title),
@@ -123,8 +123,7 @@ public class UpdaterService extends Service {
                     handleInstallProgress(update);
                 } else if (UpdaterController.ACTION_UPDATE_REMOVED.equals(intent.getAction())) {
                     Bundle extras = mNotificationBuilder.getExtras();
-                    if (extras != null && downloadId.equals(
-                            extras.getString(UpdaterController.EXTRA_DOWNLOAD_ID))) {
+                    if (downloadId.equals(extras.getString(UpdaterController.EXTRA_DOWNLOAD_ID))) {
                         mNotificationBuilder.setExtras(null);
                         UpdateInfo update = mUpdaterController.getUpdate(downloadId);
                         if (update.getStatus() != UpdateStatus.INSTALLED) {
diff --git a/src/org/lineageos/updater/download/DownloadClient.java b/src/org/lineageos/updater/download/DownloadClient.java
index 6a2a4906..34949478 100644
--- a/src/org/lineageos/updater/download/DownloadClient.java
+++ b/src/org/lineageos/updater/download/DownloadClient.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2017 The LineageOS Project
+ * Copyright (C) 2017-2022 The LineageOS Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,27 +17,23 @@ package org.lineageos.updater.download;
 
 import java.io.File;
 import java.io.IOException;
-import java.util.List;
-import java.util.Map;
 
 public interface DownloadClient {
 
     interface DownloadCallback {
-        void onResponse(int statusCode, String url, Headers headers);
+        void onResponse(Headers headers);
 
-        void onSuccess(File destination);
+        void onSuccess();
 
         void onFailure(boolean cancelled);
     }
 
     interface ProgressListener {
-        void update(long bytesRead, long contentLength, long speed, long eta, boolean done);
+        void update(long bytesRead, long contentLength, long speed, long eta);
     }
 
     interface Headers {
         String get(String name);
-
-        Map<String, List<String>> getAll();
     }
 
     /**
diff --git a/src/org/lineageos/updater/download/HttpURLConnectionClient.java b/src/org/lineageos/updater/download/HttpURLConnectionClient.java
index 2b7c80e3..8ba804ea 100644
--- a/src/org/lineageos/updater/download/HttpURLConnectionClient.java
+++ b/src/org/lineageos/updater/download/HttpURLConnectionClient.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2017 The LineageOS Project
+ * Copyright (C) 2017-2022 The LineageOS Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -51,10 +51,6 @@ public class HttpURLConnectionClient implements DownloadClient {
             return mClient.getHeaderField(name);
         }
 
-        @Override
-        public Map<String, List<String>> getAll() {
-            return mClient.getHeaderFields();
-        }
     }
 
     HttpURLConnectionClient(String url, File destination,
@@ -179,8 +175,8 @@ public class HttpURLConnectionClient implements DownloadClient {
             String protocol = mClient.getURL().getProtocol();
 
             class DuplicateLink {
-                private String mUrl;
-                private int mPriority;
+                private final String mUrl;
+                private final int mPriority;
                 private DuplicateLink(String url, int priority) {
                     mUrl = url;
                     mPriority = priority;
@@ -233,9 +229,11 @@ public class HttpURLConnectionClient implements DownloadClient {
                 } catch (IOException e) {
                     if (duplicates != null && !duplicates.isEmpty()) {
                         DuplicateLink link = duplicates.poll();
-                        duplicates.remove(link);
-                        newUrl = link.mUrl;
-                        Log.e(TAG, "Using duplicate link " + link.mUrl, e);
+                        if (link != null) {
+                            duplicates.remove(link);
+                            newUrl = link.mUrl;
+                            Log.e(TAG, "Using duplicate link " + link.mUrl, e);
+                        }
                     } else {
                         throw e;
                     }
@@ -255,7 +253,7 @@ public class HttpURLConnectionClient implements DownloadClient {
                     responseCode = mClient.getResponseCode();
                 }
 
-                mCallback.onResponse(responseCode, mClient.getURL().toString(), new Headers());
+                mCallback.onResponse(new Headers());
 
                 if (mResume && isPartialContentCode(responseCode)) {
                     mTotalBytesRead = mDestination.length();
@@ -279,12 +277,11 @@ public class HttpURLConnectionClient implements DownloadClient {
                         calculateSpeed();
                         calculateEta();
                         if (mProgressListener != null) {
-                            mProgressListener.update(mTotalBytesRead, mTotalBytes, mSpeed, mEta,
-                                    false);
+                            mProgressListener.update(mTotalBytesRead, mTotalBytes, mSpeed, mEta);
                         }
                     }
                     if (mProgressListener != null) {
-                        mProgressListener.update(mTotalBytesRead, mTotalBytes, mSpeed, mEta, true);
+                        mProgressListener.update(mTotalBytesRead, mTotalBytes, mSpeed, mEta);
                     }
 
                     outputStream.flush();
@@ -292,7 +289,7 @@ public class HttpURLConnectionClient implements DownloadClient {
                     if (isInterrupted()) {
                         mCallback.onFailure(true);
                     } else {
-                        mCallback.onSuccess(mDestination);
+                        mCallback.onSuccess();
                     }
                 }
             } catch (IOException e) {
diff --git a/src/org/lineageos/updater/misc/FileUtils.java b/src/org/lineageos/updater/misc/FileUtils.java
index fab50e6e..3226c861 100644
--- a/src/org/lineageos/updater/misc/FileUtils.java
+++ b/src/org/lineageos/updater/misc/FileUtils.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2017 The LineageOS Project
+ * Copyright (C) 2017-2022 The LineageOS Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -34,9 +34,9 @@ public class FileUtils {
     }
 
     private static class CallbackByteChannel implements ReadableByteChannel {
-        private ProgressCallBack mCallback;
-        private long mSize;
-        private ReadableByteChannel mReadableByteChannel;
+        private final ProgressCallBack mCallback;
+        private final long mSize;
+        private final ReadableByteChannel mReadableByteChannel;
         private long mSizeRead;
         private int mProgress;
 
@@ -86,13 +86,10 @@ public class FileUtils {
         } catch (IOException e) {
             Log.e(TAG, "Could not copy file", e);
             if (destFile.exists()) {
+                //noinspection ResultOfMethodCallIgnored
                 destFile.delete();
             }
             throw e;
         }
     }
-
-    public static void copyFile(File sourceFile, File destFile) throws IOException {
-        copyFile(sourceFile, destFile, null);
-    }
 }
diff --git a/src/org/lineageos/updater/misc/StringGenerator.java b/src/org/lineageos/updater/misc/StringGenerator.java
index fd11fcef..876542cf 100644
--- a/src/org/lineageos/updater/misc/StringGenerator.java
+++ b/src/org/lineageos/updater/misc/StringGenerator.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2017 The LineageOS Project
+ * Copyright (C) 2017-2022 The LineageOS Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -36,13 +36,6 @@ public final class StringGenerator {
         return f.format(date);
     }
 
-    public static String getTimeLocalizedUTC(Context context, long unixTimestamp) {
-        DateFormat f = DateFormat.getTimeInstance(DateFormat.SHORT, getCurrentLocale(context));
-        f.setTimeZone(TimeZone.getTimeZone("UTC"));
-        Date date = new Date(unixTimestamp * 1000);
-        return f.format(date);
-    }
-
     public static String getDateLocalized(Context context, int dateFormat, long unixTimestamp) {
         DateFormat f = DateFormat.getDateInstance(dateFormat, getCurrentLocale(context));
         Date date = new Date(unixTimestamp * 1000);
@@ -56,13 +49,6 @@ public final class StringGenerator {
         return f.format(date);
     }
 
-    public static String getDateTimeLocalized(Context context, long unixTimestamp) {
-        DateFormat f = DateFormat.getDateTimeInstance(DateFormat.LONG, DateFormat.SHORT,
-                getCurrentLocale(context));
-        Date date = new Date(unixTimestamp * 1000);
-        return f.format(date);
-    }
-
     public static String bytesToMegabytes(Context context, long bytes) {
         return String.format(getCurrentLocale(context), "%.0f", bytes / 1024.f / 1024.f);
     }
diff --git a/src/org/lineageos/updater/misc/Utils.java b/src/org/lineageos/updater/misc/Utils.java
index 0aa5fd53..79ded8f2 100644
--- a/src/org/lineageos/updater/misc/Utils.java
+++ b/src/org/lineageos/updater/misc/Utils.java
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2017-2021 The LineageOS Project
+ * Copyright (C) 2017-2022 The LineageOS Project
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -24,7 +24,6 @@ import android.content.SharedPreferences;
 import android.content.pm.PackageManager;
 import android.net.ConnectivityManager;
 import android.net.NetworkInfo;
-import android.os.Environment;
 import android.os.SystemProperties;
 import android.os.storage.StorageManager;
 import android.preference.PreferenceManager;
@@ -122,14 +121,14 @@ public class Utils {
             throws IOException, JSONException {
         List<UpdateInfo> updates = new ArrayList<>();
 
-        String json = "";
+        StringBuilder json = new StringBuilder();
         try (BufferedReader br = new BufferedReader(new FileReader(file))) {
             for (String line; (line = br.readLine()) != null;) {
-                json += line;
+                json.append(line);
             }
         }
 
-        JSONObject obj = new JSONObject(json);
+        JSONObject obj = new JSONObject(json.toString());
         JSONArray updatesList = obj.getJSONArray("response");
         for (int i = 0; i < updatesList.length(); i++) {
             if (updatesList.isNull(i)) {
@@ -186,15 +185,13 @@ public class Utils {
     }
 
     public static boolean isNetworkAvailable(Context context) {
-        ConnectivityManager cm = (ConnectivityManager) context.getSystemService(
-                Context.CONNECTIVITY_SERVICE);
+        ConnectivityManager cm = context.getSystemService(ConnectivityManager.class);
         NetworkInfo info = cm.getActiveNetworkInfo();
         return !(info == null || !info.isConnected() || !info.isAvailable());
     }
 
     public static boolean isOnWifiOrEthernet(Context context) {
-        ConnectivityManager cm = (ConnectivityManager) context.getSystemService(
-                Context.CONNECTIVITY_SERVICE);
+        ConnectivityManager cm = context.getSystemService(ConnectivityManager.class);
         NetworkInfo info = cm.getActiveNetworkInfo();
         return (info != null && (info.getType() == ConnectivityManager.TYPE_ETHERNET
                 || info.getType() == ConnectivityManager.TYPE_WIFI));
@@ -206,8 +203,6 @@ public class Utils {
      * @param oldJson old update list
      * @param newJson new update list
      * @return true if newJson has at least a compatible update not available in oldJson
-     * @throws IOException
-     * @throws JSONException
      */
     public static boolean checkForNewUpdates(File oldJson, File newJson)
             throws IOException, JSONException {
@@ -264,6 +259,7 @@ public class Utils {
             return;
         }
         for (File file : uncryptFiles) {
+            //noinspection ResultOfMethodCallIgnored
             file.delete();
         }
     }
@@ -273,7 +269,6 @@ public class Utils {
      * the user can't access and that might have stale files. This can happen if
      * the data of the application are wiped.
      *
-     * @param context
      */
     public static void cleanupDownloadsDir(Context context) {
         File downloadPath = getDownloadPath(context);
@@ -290,6 +285,7 @@ public class Utils {
                 lastUpdatePath != null) {
             File lastUpdate = new File(lastUpdatePath);
             if (lastUpdate.exists()) {
+                //noinspection ResultOfMethodCallIgnored
                 lastUpdate.delete();
                 // Remove the pref not to delete the file if re-downloaded
                 preferences.edit().remove(Constants.PREF_INSTALL_PACKAGE_PATH).apply();
@@ -319,6 +315,7 @@ public class Utils {
         for (File file : files) {
             if (!knownPaths.contains(file.getAbsolutePath())) {
                 Log.d(TAG, "Deleting " + file.getAbsolutePath());
+                //noinspection ResultOfMethodCallIgnored
                 file.delete();
             }
         }
@@ -367,7 +364,8 @@ public class Utils {
         return context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_TOUCHSCREEN);
     }
 
-    public static void addToClipboard(Context context, String label, String text, String toastMessage) {
+    public static void addToClipboard(Context context, String label, String text,
+                                      String toastMessage) {
         ClipboardManager clipboard = (ClipboardManager) context.getSystemService(
                 Context.CLIPBOARD_SERVICE);
         ClipData clip = ClipData.newPlainText(label, text);
diff --git a/src/org/lineageos/updater/model/Update.java b/src/org/lineageos/updater/model/Update.java
index 3ad17dea..ff778495 100644
--- a/src/org/lineageos/updater/model/Update.java
+++ b/src/org/lineageos/updater/model/Update.java
@@ -32,10 +32,6 @@ public class Update extends UpdateBase implements UpdateInfo {
     public Update() {
     }
 
-    public Update(UpdateBaseInfo update) {
-        super(update);
-    }
-
     public Update(UpdateInfo update) {
         super(update);
         mStatus = update.getStatus();
diff --git a/src/org/lineageos/updater/model/UpdateStatus.java b/src/org/lineageos/updater/model/UpdateStatus.java
index 1de988e0..12e121b0 100644
--- a/src/org/lineageos/updater/model/UpdateStatus.java
+++ b/src/org/lineageos/updater/model/UpdateStatus.java
@@ -19,7 +19,6 @@ public enum UpdateStatus {
     UNKNOWN,
     STARTING,
     DOWNLOADING,
-    DOWNLOADED,
     PAUSED,
     PAUSED_ERROR,
     DELETED,
diff --git a/src/org/lineageos/updater/ui/FlingBehavior.java b/src/org/lineageos/updater/ui/FlingBehavior.java
index fc9f3410..02655242 100644
--- a/src/org/lineageos/updater/ui/FlingBehavior.java
+++ b/src/org/lineageos/updater/ui/FlingBehavior.java
@@ -4,6 +4,7 @@ import android.content.Context;
 import android.util.AttributeSet;
 import android.view.View;
 
+import androidx.annotation.NonNull;
 import androidx.coordinatorlayout.widget.CoordinatorLayout;
 import androidx.recyclerview.widget.RecyclerView;
 
@@ -21,8 +22,9 @@ public final class FlingBehavior extends AppBarLayout.Behavior {
     }
 
     @Override
-    public boolean onNestedFling(CoordinatorLayout coordinatorLayout, AppBarLayout child,
-            View target, float velocityX, float velocityY, boolean consumed) {
+    public boolean onNestedFling(@NonNull CoordinatorLayout coordinatorLayout,
+                                 @NonNull AppBarLayout child, @NonNull View target,
+                                 float velocityX, float velocityY, boolean consumed) {
         if (velocityY > 0 && !isPositive || velocityY < 0 && isPositive) {
             velocityY = velocityY * -1;
         }
@@ -37,9 +39,10 @@ public final class FlingBehavior extends AppBarLayout.Behavior {
     }
 
     @Override
-    public void onNestedPreScroll(CoordinatorLayout coordinatorLayout, AppBarLayout child,
-            View target, int dx, int dy, int[] consumed) {
-        super.onNestedPreScroll(coordinatorLayout, child, target, dx, dy, consumed);
+    public void onNestedPreScroll(@NonNull CoordinatorLayout coordinatorLayout,
+                                  @NonNull AppBarLayout child, @NonNull View target,
+                                  int dx, int dy, @NonNull int[] consumed, int type) {
+        super.onNestedPreScroll(coordinatorLayout, child, target, dx, dy, consumed, type);
         isPositive = dy > 0;
     }
 }