Add final modifiers

app/src/androidTest/java/org/tasks/caldav/AppleRemindersTests.java

@@ -15,7 +15,7 @@ import org.tasks.time.DateTime;
 @RunWith(AndroidJUnit4.class)
 public class AppleRemindersTests {
 
-  private TimeZone defaultTimeZone = TimeZone.getDefault();
+  private final TimeZone defaultTimeZone = TimeZone.getDefault();
 
   @Before
   public void before() {

app/src/androidTest/java/org/tasks/caldav/NextCloudTests.java

@@ -15,7 +15,7 @@ import org.tasks.time.DateTime;
 @RunWith(AndroidJUnit4.class)
 public class NextCloudTests {
 
-  private TimeZone defaultTimeZone = TimeZone.getDefault();
+  private final TimeZone defaultTimeZone = TimeZone.getDefault();
 
   @Before
   public void before() {

app/src/androidTest/java/org/tasks/caldav/SynologyTests.java

@@ -13,7 +13,7 @@ import org.junit.runner.RunWith;
 @RunWith(AndroidJUnit4.class)
 public class SynologyTests {
 
-  private TimeZone defaultTimeZone = TimeZone.getDefault();
+  private final TimeZone defaultTimeZone = TimeZone.getDefault();
 
   @Before
   public void before() {

app/src/androidTest/java/org/tasks/caldav/ThunderbirdTests.java

@@ -15,7 +15,7 @@ import org.tasks.time.DateTime;
 @RunWith(AndroidJUnit4.class)
 public class ThunderbirdTests {
 
-  private TimeZone defaultTimeZone = TimeZone.getDefault();
+  private final TimeZone defaultTimeZone = TimeZone.getDefault();
 
   @Before
   public void before() {

app/src/main/java/com/todoroo/astrid/activity/TaskListFragment.java

@@ -185,7 +185,7 @@ public final class TaskListFragment extends InjectingFragment
   private TaskAdapter taskAdapter = null;
   private TaskListRecyclerAdapter recyclerAdapter;
   private Filter filter;
-  private PublishSubject<String> searchSubject = PublishSubject.create();
+  private final PublishSubject<String> searchSubject = PublishSubject.create();
   private Disposable searchDisposable;
   private MenuItem search;
   private String searchQuery;

app/src/main/java/com/todoroo/astrid/adapter/NavigationDrawerAdapter.java

@@ -54,7 +54,7 @@ public class NavigationDrawerAdapter extends RecyclerView.Adapter<ViewHolder> {
   private OnClick onClick;
   private Filter selected = null;
 
-  private AsyncListDiffer<FilterListItem> differ;
+  private final AsyncListDiffer<FilterListItem> differ;
 
   @Inject
   public NavigationDrawerAdapter(

app/src/main/java/org/tasks/activities/FilterSelectionActivity.java

@@ -33,7 +33,7 @@ public class FilterSelectionActivity extends InjectingAppCompatActivity {
 
   private CompositeDisposable disposables;
   private Filter selected;
-  private BroadcastReceiver refreshReceiver = new BroadcastReceiver() {
+  private final BroadcastReceiver refreshReceiver = new BroadcastReceiver() {
     @Override
     public void onReceive(Context context, Intent intent) {
       refresh();

app/src/main/java/org/tasks/activities/RemoteListPicker.java

@@ -43,7 +43,7 @@ public class RemoteListPicker extends InjectingDialogFragment
   @Inject LocalBroadcastManager localBroadcastManager;
 
   private CompositeDisposable disposables;
-  private BroadcastReceiver refreshReceiver = new BroadcastReceiver() {
+  private final BroadcastReceiver refreshReceiver = new BroadcastReceiver() {
     @Override
     public void onReceive(Context context, Intent intent) {
       refresh();

app/src/main/java/org/tasks/backup/TasksJsonImporter.java

@@ -66,7 +66,7 @@ public class TasksJsonImporter {
   private final Preferences preferences;
   private final LocationDao locationDao;
 
-  private ImportResult result = new ImportResult();
+  private final ImportResult result = new ImportResult();
 
   @Inject
   public TasksJsonImporter(

app/src/main/java/org/tasks/billing/Inventory.java

@@ -21,7 +21,7 @@ public class Inventory {
   private final SignatureVerifier signatureVerifier;
   private final LocalBroadcastManager localBroadcastManager;
 
-  private Map<String, Purchase> purchases = new HashMap<>();
+  private final Map<String, Purchase> purchases = new HashMap<>();
   private Purchase subscription = null;
 
   @Inject

app/src/main/java/org/tasks/dialogs/IconLayoutManager.java

@@ -7,7 +7,7 @@ import org.tasks.R;
 
 public class IconLayoutManager extends GridLayoutManager {
 
-  private int iconSize;
+  private final int iconSize;
 
   public IconLayoutManager(Context context) {
     super(context, DEFAULT_SPAN_COUNT, RecyclerView.VERTICAL, false);

app/src/main/java/org/tasks/filters/AlphanumComparator.java

@@ -43,7 +43,7 @@ import java.util.Comparator;
  */
 public class AlphanumComparator<T> implements Comparator<T> {
 
-  public static Function<Filter, String> FILTER = f -> f.listingTitle;
+  public static final Function<Filter, String> FILTER = f -> f.listingTitle;
 
   private final Function<T, String> getTitle;
 

app/src/main/java/org/tasks/filters/PlaceFilter.java

@@ -37,7 +37,7 @@ public class PlaceFilter extends Filter {
         }
       };
 
-  private Place place;
+  private final Place place;
   private static final Table G2 = Geofence.TABLE.as("G2");
   private static final Field G2_PLACE = Field.field("G2.place");
   private static final Field G2_TASK = Field.field("G2.task");

app/src/main/java/org/tasks/jobs/WorkManager.java

@@ -62,7 +62,7 @@ public class WorkManager {
   private final GoogleTaskListDao googleTaskListDao;
   private final CaldavDao caldavDao;
   private final AlarmManager alarmManager;
-  private androidx.work.WorkManager workManager;
+  private final androidx.work.WorkManager workManager;
 
   @Inject
   public WorkManager(

app/src/main/java/org/tasks/location/LocationPickerActivity.java

@@ -125,7 +125,7 @@ public class LocationPickerActivity extends InjectingAppCompatActivity
   private List<PlaceUsage> places = Collections.emptyList();
   private int offset;
   private MenuItem search;
-  private PublishSubject<String> searchSubject = PublishSubject.create();
+  private final PublishSubject<String> searchSubject = PublishSubject.create();
   private PlaceSearchViewModel viewModel;
 
   @Override

app/src/main/java/org/tasks/location/LocationSearchAdapter.java

@@ -129,7 +129,7 @@ public class LocationSearchAdapter extends RecyclerView.Adapter<ViewHolder>
 
   public static class FooterViewHolder extends RecyclerView.ViewHolder {
 
-    View divider;
+    final View divider;
 
     FooterViewHolder(@NonNull View itemView, @DrawableRes int attributionRes) {
       super(itemView);

app/src/main/java/org/tasks/location/MapboxMapFragment.java

@@ -31,7 +31,7 @@ public class MapboxMapFragment implements MapFragment, OnMapReadyCallback, OnMar
   private MapFragmentCallback callbacks;
   private boolean dark;
   private MapboxMap map;
-  private Map<Marker, Place> markers = new HashMap<>();
+  private final Map<Marker, Place> markers = new HashMap<>();
 
   public MapboxMapFragment(Context context) {
     this.context = context;

app/src/main/java/org/tasks/location/PlaceSearchViewModel.java

@@ -17,9 +17,9 @@ import org.tasks.data.Place;
 public class PlaceSearchViewModel extends ViewModel {
   private PlaceSearchProvider searchProvider;
 
-  private MutableLiveData<List<PlaceSearchResult>> searchResults = new MutableLiveData<>();
-  private MutableLiveData<Event<String>> error = new MutableLiveData<>();
-  private MutableLiveData<Place> selection = new MutableLiveData<>();
+  private final MutableLiveData<List<PlaceSearchResult>> searchResults = new MutableLiveData<>();
+  private final MutableLiveData<Event<String>> error = new MutableLiveData<>();
+  private final MutableLiveData<Place> selection = new MutableLiveData<>();
 
   void setSearchProvider(PlaceSearchProvider searchProvider) {
     this.searchProvider = searchProvider;

app/src/main/java/org/tasks/tasklist/DragAndDropRecyclerAdapter.java

@@ -37,9 +37,9 @@ public class DragAndDropRecyclerAdapter extends TaskListRecyclerAdapter {
   private final TaskListFragment taskList;
   private final RecyclerView recyclerView;
   private List<TaskContainer> list;
-  private PublishSubject<List<TaskContainer>> publishSubject = PublishSubject.create();
-  private CompositeDisposable disposables = new CompositeDisposable();
-  private Queue<Pair<List<TaskContainer>, DiffResult>> updates = new LinkedList<>();
+  private final PublishSubject<List<TaskContainer>> publishSubject = PublishSubject.create();
+  private final CompositeDisposable disposables = new CompositeDisposable();
+  private final Queue<Pair<List<TaskContainer>, DiffResult>> updates = new LinkedList<>();
   private boolean dragging;
 
   public DragAndDropRecyclerAdapter(

app/src/main/java/org/tasks/tasklist/PagedListRecyclerAdapter.java

@@ -14,7 +14,7 @@ import org.tasks.data.TaskContainer;
 public class PagedListRecyclerAdapter extends TaskListRecyclerAdapter {
 
   private final RecyclerView recyclerView;
-  private AsyncPagedListDiffer<TaskContainer> differ;
+  private final AsyncPagedListDiffer<TaskContainer> differ;
 
   public PagedListRecyclerAdapter(
       TaskAdapter adapter,

app/src/main/java/org/tasks/ui/TaskListViewModel.java

@@ -40,7 +40,7 @@ public class TaskListViewModel extends ViewModel implements Observer<PagedList<T
   private MutableLiveData<List<TaskContainer>> tasks = new MutableLiveData<>();
   private Filter filter;
   private boolean manualSort;
-  private CompositeDisposable disposable = new CompositeDisposable();
+  private final CompositeDisposable disposable = new CompositeDisposable();
   private LiveData<PagedList<TaskContainer>> internal;
 
   public void setFilter(@NonNull Filter filter) {