FusedLocationProviderClient.java

   private FusedLocationProviderClient fusedLocationProviderClient;
   private LocationRequest locationRequest;   
   private LocationCallback locationCallback;

   fusedLocationProviderClient = LocationServices.getFusedLocationProviderClient(this);
   
   fusedLocationProviderClient.getLastLocation().addOnSuccessListener(new OnSuccessListener<Location>() {
            @Override
            public void onSuccess(Location location) {
                if (location != null) {
                 //do something
                } 
            }
        });
        
    locationRequest = new LocationRequest();
    locationRequest.setInterval(2000);
    locationRequest.setFastestInterval(2000);
    locationRequest.setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY);
    locationCallback = new LocationCallback() {
            @Override
            public void onLocationResult(LocationResult locationResult) {
                super.onLocationResult(locationResult);
                for (Location location : locationResult.getLocations()) {
                    if (location != null) {
                       //do something
                    }
                }
            }
        };
    
    fusedLocationProviderClient.requestLocationUpdates(locationRequest, locationCallback, getMainLooper());