Q:

The String#value field is not present on Android versions >= 6.0

I am creating an app like Uber but I have ran into a problem after I got an error suddenly and the app crashed.  I tried out many ways in order to get ride of this error but it didn't work.  All the answers to the similar questions that I could find on Stackoverflow were that this problem is caused due to FirebaseDatabase.getInstance().setPersistenceEnabled(true) and I had to delete this code of line as this is a bug with Firebase that is yet to be solved.  But this didn't solve my problem as i didn't have any such code.  That's why i thought this is a question which is not on stackoverflow and asked the question.  This is my Java Code
package com.matt.autozauser;

import com.directions.route. AbstractRouting;
import com.directions.route. Route;
import com.directions.route. RouteException;
import com.directions.route. Routing;
import com.directions.route. RoutingListener;
import com.firebase.geofire. GeoFire;
import com.firebase.geofire. GeoLocation;
import com.firebase.geofire. GeoQuery;
import com.firebase.geofire. GeoQueryEventListener;
import com.google.android.gms.common. GooglePlayServicesUtil;
import com.google.android.gms.location. LocationListener;
import com.google.android.gms.location. LocationServices;
import com.google.android.gms.location.places.ui. PlaceAutocomplete;
import com.google.android.gms.location.places.ui. PlaceAutocompleteFragment;
import com.google.android.gms.maps. CameraUpdateFactory;
import com.google.android.gms.maps.model. BitmapDescriptorFactory;
import com.google.android.gms.maps.model. LatLng;

import android. Manifest;
import android.content.pm. PackageManager;
import android.location. Location;
import android.location. LocationManager;
import android.support.annotation. NonNull;
import android.support.annotation. Nullable;
import android.support.v4.app. ActivityCompat;
import android.support.v4.app. FragmentActivity;
import android.os. Bundle;
import android.support.v4.content. ContextCompat;
import android.support.v7.widget. LinearLayoutManager;
import android.support.v7.widget. RecyclerView;
import android.util. Log;
import android.view. View;
import android.widget. Button;
import android.widget. Toast;

import com.google.android.gms.common. ConnectionResult;
import com.google.android.gms.common.api. GoogleApiClient;
import com.google.android.gms.location. LocationRequest;
import com.google.android.gms.maps. GoogleMap;
import com.google.android.gms.maps. OnMapReadyCallback;
import com.google.android.gms.maps. SupportMapFragment;
import com.google.android.gms.maps.model. Marker;
import com.google.android.gms.maps.model. MarkerOptions;
import com.google.firebase.auth. FirebaseAuth;
import com.google.firebase.database. DataSnapshot;
import com.google.firebase.database. DatabaseError;
import com.google.firebase.database. DatabaseReference;
import com.google.firebase.database. FirebaseDatabase;
import com.google.firebase.database. ValueEventListener;

import java.util. ArrayList;
import java.util. HashMap;
import java.util. List;

public class Welcome extends FragmentActivity implements OnMapReadyCallback,
        GoogleApiClient. ConnectionCallbacks,
        GoogleApiClient. OnConnectionFailedListener,
        LocationListener{

SupportMapFragment mapFragment;

private Button btnBooking;
private Location lastLocation;
private GoogleApiClient. OnConnectionFailedListener onConnectionFailedListener;
private LocationRequest locationRequest;
private LocationListener locationListener;
private LocationManager locationManager;
private Marker marker, driverMarker;
private GoogleMap mMap;
private GoogleApiClient googleApiClient;
private final int RequestCode = 10;
private final int ResourceCode = 11;
private DatabaseReference userLastLocation, customersUnderServiceRef, userRequest, driversOnDuty,workingDrivers, driverRef1, driverWorkingRef ;
GeoFire location, onDuty, customersUnderService;
private Boolean clicked = false;
private String driverID = "";
private ValueEventListener driverListener;
private GeoQuery geoQuery;
private String myId = "";
private Double driverLat, driverLng;
private PlaceAutocomplete pickup, drop;

@Override
protected void onCreate(Bundle savedInstanceState)
{
    checkLocationPermission();
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_welcome);
    mapFragment = (SupportMapFragment)
            getSupportFragmentManager()
                    .findFragmentById(R.id.map);
    mapFragment.getMapAsync(this);
    locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);

    userLastLocation = FirebaseDatabase.getInstance().getReference("User LastLocation");
    location = new GeoFire(userLastLocation);
    setupLocation();

    driversOnDuty = FirebaseDatabase.getInstance().getReference("DriversOnDuty");
    onDuty = new GeoFire(driversOnDuty);

    driverWorkingRef = FirebaseDatabase.getInstance().getReference().child("DriversWorking");

    customersUnderServiceRef = FirebaseDatabase.getInstance().getReference().child("CustomersUnderService");
    customersUnderService = new GeoFire(customersUnderServiceRef);

}

@Override
public void onMapReady(GoogleMap googleMap)
{
    myId = FirebaseAuth.getInstance().getCurrentUser().getUid();
    setupUiViews();
    mMap = googleMap;
    displayLocation();

}

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults)
{
    switch (requestCode) {
        case RequestCode:
            if (grantResults.length > 0 && grantResults[0] == PackageManager. PERMISSION_GRANTED) {
                if (checkPlayServices()){
                    buildGoogleApiClient();
                    createLocationRequest();
                    displayLocation();
                }
            }
            break;
    }
}

@Override
public void onConnected(@Nullable Bundle bundle)
{
    if (ContextCompat.checkSelfPermission(this, Manifest.permission. ACCESS_FINE_LOCATION) == PackageManager. PERMISSION_GRANTED
            && ContextCompat.checkSelfPermission(this, Manifest.permission. ACCESS_COARSE_LOCATION) == PackageManager. PERMISSION_GRANTED){

        if (googleApiClient == null){
            buildGoogleApiClient();
        }
        if (! googleApiClient.isConnected()){
            googleApiClient.connect();
        }
        startLocationUpdates();
        displayLocation2();

        locationRequest = LocationRequest
                .create()
                .setInterval(1000)
                .setFastestInterval(500)
                .setPriority(LocationRequest. PRIORITY_HIGH_ACCURACY);

        startLocationUpdates();
        displayLocation();

    }else {
        checkLocationPermission();
    }

}

@Override
public void onConnectionSuspended(int i)

{
    googleApiClient.connect();
}

@Override
public void onConnectionFailed(@NonNull ConnectionResult connectionResult)
{
}

@Override
public void onLocationChanged(Location location)
{
    lastLocation = location;
    displayLocation2();

}

public void checkLocationPermission()
{
    if (ContextCompat.checkSelfPermission(this, Manifest.permission. ACCESS_FINE_LOCATION) ! = PackageManager. PERMISSION_GRANTED)
    {
        if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission. ACCESS_FINE_LOCATION))
        {
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission. ACCESS_FINE_LOCATION}, RequestCode);
        } else {
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission. ACCESS_FINE_LOCATION}, RequestCode);
        }
    }
}

protected synchronized void buildGoogleApiClient()
{
    googleApiClient = new GoogleApiClient. Builder(this)
            .addConnectionCallbacks(this)
            .addOnConnectionFailedListener(this)
            .addApi(LocationServices. API)
            .build();
    googleApiClient.connect();
}

private void setupUiViews()

{
    btnBooking = findViewById(R.id.bookingButton);
    btnBooking.setOnClickListener(new View. OnClickListener() {
        @Override
        public void onClick(View v) {
            if (clicked == false) {
                Toast.makeText(Welcome.this, "Getting Cab", Toast. LENGTH_SHORT).show();
                btnBooking.setText(R.string.gettingCab);
                clicked = true;
                getNearestDriver();
            } else
            {
                if(!driverFound){
                    btnBooking.setText(R.string.callTaxi);

                    stopLocationUpdates();
                    String userId = FirebaseAuth.getInstance().getCurrentUser().getUid();
                    DatabaseReference databaseReference1 = FirebaseDatabase.getInstance().getReference("Customer Request");
                    GeoFire geoFire1 = new GeoFire(databaseReference1);
                    geoFire1.removeLocation(userId);
                    Toast.makeText(Welcome.this, "Canceling Cab", Toast. LENGTH_SHORT).show();
                    if(driverMarker!=null){
                        driverMarker.remove();
                    }
                    clicked = false;
                }
            }
        }
    });
}

private void displayLocation()

{
    if (ActivityCompat.checkSelfPermission(this, Manifest.permission. ACCESS_FINE_LOCATION) ! = PackageManager. PERMISSION_GRANTED &&
            ActivityCompat.checkSelfPermission(this, Manifest.permission. ACCESS_COARSE_LOCATION) ! = PackageManager. PERMISSION_GRANTED)
    {
        return;
    }
    lastLocation = LocationServices. FusedLocationApi.getLastLocation(googleApiClient);
    if (lastLocation ! = null ){
        final Double lat = lastLocation.getLatitude();
        final Double lng = lastLocation.getLongitude();

        location.setLocation(FirebaseAuth.getInstance().getCurrentUser().getUid(), new GeoLocation(lat, lng), new GeoFire. CompletionListener()
        {
            @Override
            public void onComplete(String key, DatabaseError error) {
                if (marker ! = null) {
                    marker.remove();
                    marker = mMap.addMarker(new MarkerOptions().position(new LatLng(lat, lng)).icon(BitmapDescriptorFactory.fromResource(R.drawable.location_marker)).title("You"));

                    mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(lat, lng), 15.0f));
                }else{
                    marker = mMap.addMarker(new MarkerOptions().position(new LatLng(lat, lng)).icon(BitmapDescriptorFactory.fromResource(R.drawable.location_marker)).title("You"));

                    mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(lat, lng), 15.0f));
                }
            }
        });

    }else{
        Log.d("Error", "Cannot Get Your Location");
    }
}

private void displayLocation2()
{
    if (ActivityCompat.checkSelfPermission(this, Manifest.permission. ACCESS_FINE_LOCATION) ! = PackageManager. PERMISSION_GRANTED &&
            ActivityCompat.checkSelfPermission(this, Manifest.permission. ACCESS_COARSE_LOCATION) ! = PackageManager. PERMISSION_GRANTED)
    {
        return;
    }
    lastLocation = LocationServices. FusedLocationApi.getLastLocation(googleApiClient);
    if (lastLocation ! = null ){
        if(clicked == true){
            if (marker ! = null){
                marker.remove();
            }
            final Double lat = lastLocation.getLatitude();
            final Double lng = lastLocation.getLongitude();

            customersUnderService.setLocation(FirebaseAuth.getInstance().getCurrentUser().getUid(), new GeoLocation(lat, lng), new GeoFire. CompletionListener()
            {
                @Override
                public void onComplete(String key, DatabaseError error) {
                    if (marker ! = null) {
                        marker.remove();
                        marker = mMap.addMarker(new MarkerOptions().position(new LatLng(lat, lng)).icon(BitmapDescriptorFactory.fromResource(R.drawable.location_marker)).title("You"));

                    }else{
                        marker = mMap.addMarker(new MarkerOptions().position(new LatLng(lat, lng)).icon(BitmapDescriptorFactory.fromResource(R.drawable.location_marker)).title("You"));
                    }
                }
            });
        }
    }else{
        Log.d("Error", "Cannot Get Your Location");
    }
}

private void setupLocation()
{
    if (ContextCompat.checkSelfPermission(this, Manifest.permission. ACCESS_FINE_LOCATION) ! = PackageManager. PERMISSION_GRANTED)
    {
        if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission. ACCESS_FINE_LOCATION))
        {
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission. ACCESS_FINE_LOCATION}, RequestCode);
        } else {
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission. ACCESS_FINE_LOCATION}, RequestCode);
        }
    }else{
        if (checkPlayServices())
        {
            buildGoogleApiClient();
            createLocationRequest();

        }
    }
}

private void createLocationRequest()
{
    locationRequest = LocationRequest.create()
            .setInterval(1500)
            .setFastestInterval(500)
            .setPriority(LocationRequest. PRIORITY_HIGH_ACCURACY)
            .setSmallestDisplacement(0);
}

private boolean checkPlayServices()
{
    int resultCode = GooglePlayServicesUtil.isGooglePlayServicesAvailable(this);
    if (resultCode ! = ConnectionResult. SUCCESS)
    {
        if (GooglePlayServicesUtil.isUserRecoverableError(resultCode))
            GooglePlayServicesUtil.getErrorDialog(resultCode, this, ResourceCode).show();
        else {
            Toast.makeText(this, "This Device Is Not Supported", Toast. LENGTH_SHORT).show();
            finish();
        }return false;
    }
    return true;
}

private void stopLocationUpdates()
{
    if (ActivityCompat.checkSelfPermission(this, Manifest.permission. ACCESS_FINE_LOCATION) ! = PackageManager. PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission. ACCESS_COARSE_LOCATION) ! = PackageManager. PERMISSION_GRANTED)
    {
        return;
    }
    LocationServices. FusedLocationApi.removeLocationUpdates(googleApiClient, this);
}

private void startLocationUpdates()
{
    if (ActivityCompat.checkSelfPermission(this, Manifest.permission. ACCESS_FINE_LOCATION) ! = PackageManager. PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission. ACCESS_COARSE_LOCATION) ! = PackageManager. PERMISSION_GRANTED)
    {
        return;
    }
    LocationServices. FusedLocationApi.requestLocationUpdates(googleApiClient, locationRequest, this);
}

private int radius = 1;
private Boolean driverFound = false;

private void getNearestDriver()
{
    geoQuery = onDuty.queryAtLocation(new GeoLocation(lastLocation.getLatitude(), lastLocation.getLongitude()), radius);
    geoQuery.removeAllListeners();

    geoQuery.addGeoQueryEventListener(new GeoQueryEventListener() {
        @Override
        public void onKeyEntered(String key, GeoLocation location) {

            String driverId = key;
            if(!driverFound){
                driverFound = true;
                driverID = key;
                DatabaseReference driverRef = FirebaseDatabase.getInstance().getReference().child("DriversWorking").child(driverId);

                String customerId = FirebaseAuth.getInstance().getCurrentUser().getUid();

                HashMap map = new HashMap();
                map.put("customerRideId", customerId);
                driverRef.updateChildren(map);

                driverID = key;
                btnBooking.setText(R.string.gettingTaxiLocation);

                customersUnderService.setLocation(FirebaseAuth.getInstance().getCurrentUser().getUid(), new GeoLocation(lastLocation.getLatitude(), lastLocation.getLongitude()));

                getDriverLocation();
                driversOnDuty.child(key).removeValue();
            }
        }

        @Override
        public void onKeyExited(String key) {

        }

        @Override
        public void onKeyMoved(String key, GeoLocation location) { }

        @Override
        public void onGeoQueryReady() {
            if(!driverFound){
                radius++;
                getNearestDriver();
            }
        }

        @Override
        public void onGeoQueryError(DatabaseError error) {

        }
    });
}

private void getDriverLocation()
{
    driverWorkingRef = driverWorkingRef.child(driverID).child("l");
    driverListener = driverWorkingRef.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            if (dataSnapshot.exists()){
                List<Object> map = (List<Object>) dataSnapshot.getValue();
                double locationLat = 0;
                double locationLng = 0;

                btnBooking.setText(R.string.driverComing);

                if (map.get(0) ! = null)
                {
                    locationLat = Double.parseDouble(map.get(0).toString());
                    driverLat = locationLat;
                }

                if (map.get(1) ! = null)
                {
                    locationLng = Double.parseDouble(map.get(1).toString());
                    driverLng = locationLng;
                }

                LatLng driverLatLng = new LatLng(locationLat, locationLng);

                if (driverMarker ! = null) {
                    driverMarker.remove();
                }
                driverMarker = mMap.addMarker(new MarkerOptions().position(driverLatLng).icon(BitmapDescriptorFactory.fromResource(R.drawable.carmarker)).title("You"));
                mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(driverLatLng, 15.0f));

                Location myLoc = new Location("");
                Location driverLoc = new Location("");

                myLoc.setLatitude(lastLocation.getLatitude());
                myLoc.setLongitude(lastLocation.getLongitude());

                driverLoc.setLatitude(locationLat);
                driverLoc.setLongitude(locationLng);

                float distance = myLoc.distanceTo(driverLoc);
                ;
                if (distance<100){
                    btnBooking.setText(R.string.driverReached);

                }
            }getDriverLocation();

        }

        @Override
        public void onCancelled(DatabaseError databaseError) {

        }
    });
}  

@Override
protected void onStop()
{
    super.onStop();

}

@Override
protected void onPause() {
    super.onPause();
}
}

These are the errors in the Logcat. 
06-04 17:39:10.550 13127-13127/com.matt.autozauser E/art: The String#value field is not present on Android versions >= 6.0

06-04 17:39:11.166 13127-13358/com.matt.autozauser E/HAL: PATH3 /odm/lib64/hw/gralloc.qcom.so
    PATH2 /vendor/lib64/hw/gralloc.qcom.so
    PATH1 /system/lib64/hw/gralloc.qcom.so
    PATH3 /odm/lib64/hw/gralloc.msm8953.so
    PATH2 /vendor/lib64/hw/gralloc.msm8953.so
    PATH1 /system/lib64/hw/gralloc.msm8953.so

06-04 17:40:19.271 13127-13228/com.matt.autozauser E/NoopPersistenceManager: Caught Throwable. 
java.lang. StackOverflowError: stack size 1037KB
    at com.google.firebase.database.collection.zza.insert(Unknown Source)
    at com.google.android.gms.internal.firebase_database.zzgj.zzb(Unknown Source)
    at com.google.android.gms.internal.firebase_database.zzgj.zzb(Unknown Source)
    at com.google.android.gms.internal.firebase_database.zzgj.zzb(Unknown Source)
    at com.google.android.gms.internal.firebase_database.zzgj.zzb(Unknown Source)
    at com.google.android.gms.internal.firebase_database.zzgj.zzb(Unknown Source)
    at com.google.android.gms.internal.firebase_database.zzgj.zzb(Unknown Source)
    at com.google.android.gms.internal.firebase_database.zzgj.zzb(Unknown Source)
    at com.google.android.gms.internal.firebase_database.zzgj.zzb(Unknown Source)
    at com.google.android.gms.internal.firebase_database.zzgj.zzb(Unknown Source)
    at com.google.android.gms.internal.firebase_database.zzgj.zzb(Unknown Source)
    at com.google.android.gms.internal.firebase_database.zzgj.zzb(Unknown Source)
    at com.google.android.gms.internal.firebase_database.zzgj.zzb(Unknown Source)
    at com.google.android.gms.internal.firebase_database.zzgj.zzb...[20]

A:

You can add the following line in AndroidManifest.xml: 
<uses-library android:name="org.apache.http.legacy" android:required="false"/>

