Cleanup using AndroidStudio's code analyzer.

src/main/java/de/dennisguse/opentracks/services/TrackDeleteService.java

@@ -137,9 +137,9 @@ public class TrackDeleteService extends Service {
     }
 
     public static class DeleteStatus {
-        private int progress;
-        private int max;
-        private Track.Id trackId;
+        private final int progress;
+        private final int max;
+        private final Track.Id trackId;
 
         /**
          * @param trackId  Track.Id just deleted if any.

src/main/java/de/dennisguse/opentracks/services/TrackRecordingService.java

@@ -240,20 +240,6 @@ public class TrackRecordingService extends Service implements HandlerServer.Hand
         return trackStatisticsUpdater.getTrackStatistics();
     }
 
-    //TODO Throw exception, when not recording.
-    public Duration getTotalTime() {
-        if (trackStatisticsUpdater == null) {
-            return Duration.ofSeconds(0);
-        }
-        if (isPaused()) {
-            return trackStatisticsUpdater.getTrackStatistics().getTotalTime();
-        }
-
-        TrackStatistics statistics = trackStatisticsUpdater.getTrackStatistics();
-        return Duration.between(statistics.getStopTime(), Instant.now())
-                .plus(statistics.getTotalTime());
-    }
-
     public Marker.Id insertMarker(String name, String category, String description, String photoUrl) {
         if (!isRecording() || isPaused()) {
             return null;

src/main/java/de/dennisguse/opentracks/services/sensors/AltitudeSumManager.java

@@ -10,8 +10,6 @@ import android.util.Log;
 import androidx.annotation.Nullable;
 import androidx.annotation.VisibleForTesting;
 
-import java.time.Duration;
-
 import de.dennisguse.opentracks.util.PressureSensorUtils;
 
 /**
@@ -21,8 +19,6 @@ public class AltitudeSumManager implements SensorEventListener {
 
     private static final String TAG = AltitudeSumManager.class.getSimpleName();
 
-    private static final Duration SAMPLING_RATE = Duration.ofSeconds(3);
-
     private boolean isConnected = false;
 
     private float lastAcceptedPressureValue_hPa;