hii, To search marker based on mLabel value and automat show infowindow, See below code-

public class MapsActivity extends FragmentActivity implements OnMapReadyCallback {

    private GoogleMap mMap;
    MarkerOptions markerOptions;
    LatLng latLng;
    private GoogleMap.OnInfoWindowClickListener infoWindowClickListener;
    private HashMapmarker;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_maps);
        // Obtain the SupportMapFragment and get notified when the map is ready to be used.
        SupportMapFragment mapFragment = (SupportMapFragment) getSupportFragmentManager()
                .findFragmentById(R.id.map);
        mapFragment.getMapAsync(this);
        mMap=mapFragment.getMap();

        mMap.setInfoWindowAdapter(new GoogleMap.InfoWindowAdapter() {
            private View view;

            @Override
            public View getInfoWindow(Marker marker) {
                return view;
            }

            @Override
            public View getInfoContents(Marker marker) {
                View v = getLayoutInflater().inflate(R.layout.windowlayout, null);
                latLng = marker.getPosition();
                TextView tvLat = (TextView) v.findViewById(R.id.tv_lat);
                ImageView imageView = (ImageView) v.findViewById(R.id.marker_icon);
                TextView address = (TextView) v.findViewById(R.id.tv_palace);
                Button button = (Button) v.findViewById(R.id.button2);
                TextView tvLng = (TextView) v.findViewById(R.id.tv_lng);


                tvLat.setText("Latitude:" + latLng.latitude);
                tvLng.setText("Longitude:" + latLng.longitude);
                button.setVisibility(View.VISIBLE);


                try {
                    Geocoder geocoder = new Geocoder(MapsActivity.this.getApplicationContext(), Locale.getDefault());
                    List addresses = geocoder.getFromLocation(latLng.latitude, latLng.longitude, 1);

                    if (addresses.isEmpty()) {

                    } else {
                        if (addresses.size() > 0) {

                            address.setText("Place Name-:" + addresses.get(0).getFeatureName() + addresses.get(0).getAdminArea() + addresses.get(0).getLocality());
                            Toast.makeText(getApplicationContext(), "Address:-" + addresses.get(0).getFeatureName() + addresses.get(0).getAdminArea() + addresses.get(0).getLocality(), Toast.LENGTH_LONG).show();
                        }
                    }


                } catch (IOException e) {
                    e.printStackTrace();
                }
                tvLng.setText("Longitude" + latLng.longitude);
                button.setVisibility((View.VISIBLE));
                return v;

            }
        });
        mMap.setOnInfoWindowClickListener(new GoogleMap.OnInfoWindowClickListener() {
            @Override
            public void onInfoWindowClick(Marker marker) {
                mMap.addMarker(new MarkerOptions().position(latLng)).setVisible(true);
                CameraUpdate center = CameraUpdateFactory.newLatLng(new LatLng(40.76793169992044,
                        -73.98180484771729));
                CameraUpdate zoom = CameraUpdateFactory.zoomTo(15);

                mMap.moveCamera(center);
                mMap.animateCamera(zoom);


                Toast.makeText(MapsActivity.this, "You have clicked the window", Toast.LENGTH_SHORT).show();
            }
        });
        mMap.setOnMapClickListener(new GoogleMap.OnMapClickListener() {
            @Override
            public void onMapClick(LatLng arg0) {
                latLng=arg0;
                mMap.clear();

                MarkerOptions markerOptions= new MarkerOptions();
                markerOptions.position(latLng);

                mMap.animateCamera(CameraUpdateFactory.newLatLng(latLng));

                Marker marker = mMap.addMarker(markerOptions);

            }
        });

    }
    public void onMapSearch(View view){
        EditText locationSearch=(EditText)findViewById(R.id.editText);
        String location=locationSearch.getText().toString();
        ListaddressList=null;

        if(location!=null||!location.equals("")){
            Geocoder geocoder= new Geocoder(this);
            try{
                addressList=geocoder.getFromLocationName(location,1);
            } catch (IOException e) {
                e.printStackTrace();
            }
            Address address= addressList.get(0);
            LatLng latLng= new LatLng(address.getLatitude(),address.getLongitude());
            mMap.addMarker(new MarkerOptions().position(latLng).title("Marker"));
            mMap.animateCamera(CameraUpdateFactory.newLatLng(latLng));
        }
    }


    /**
     * Manipulates the map once available.
     * This callback is triggered when the map is ready to be used.
     * This is where we can add markers or lines, add listeners or move the camera. In this case,
     * we just add a marker near Sydney, Australia.
     * If Google Play services is not installed on the device, the user will be prompted to install
     * it inside the SupportMapFragment. This method will only be triggered once the user has
     * installed Google Play services and returned to the app.
     */
    @Override
    public void onMapReady(GoogleMap googleMap) {
        mMap = googleMap;
        mMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);

        CameraPosition googlePlex = CameraPosition.builder()
                .target(new LatLng(37.4219999,-122.0862462))
                .zoom(16)
                .bearing(0)
                .tilt(45)
                .build();

        mMap.moveCamera(CameraUpdateFactory.newCameraPosition(googlePlex));

        mMap.setMyLocationEnabled(true);
    }
}

Sir, how to search marker based on mLabel value and automat show infowindow ?