can't serialize class org.springframework.data.mongodb.core.geo.GeoJsonPoint - mongodb

Question

I am using MongoDB Near to find nearest points, getMills is method to find nearest points based on LatLng. It runs fine till fetching data and mapping. while mapping it returns following error. My question is that how can i serialize class to GeoJsonPoint???
It's returning this error : can't serialize class org.springframework.data.mongodb.core.geo.GeoJsonPoint.
private List<Mill> getMills(GetNearByMillsRequest getNearByMillsRequest, BasicResponse basicResponse) {
// get farmerPosition
LatLng fieldPosition = getNearByMillsRequest.getFieldPosition();
double Longitude = fieldPosition.getLongitude();
double Latitude = fieldPosition.getLatitude();
System.out.println("Longitude : " + Longitude + "Latitude : "+ Latitude);
// creating GeoJson Object for farmer field location...
Point point = new Point(Latitude,Longitude);
GeoJsonPoint farmerFieldPosition = new GeoJsonPoint(point);
Float distance = getNearByMillsRequest.getDistance();
// find crop by crop Name
Query query = new Query();
query.addCriteria(Criteria.where(Mill.Constants.MILL_CROP_REQUIRED).elemMatch(Criteria.where(MillCropRequired.Constants.CROP).is(getNearByMillsRequest.getCrop())));
query.addCriteria(Criteria.where(Mill.Constants.MILL_LOCATION).near(farmerFieldPosition));
// TODO Get radius from UserPreferences
NearQuery nearQuery = NearQuery.near(farmerFieldPosition).maxDistance(new Distance(distance, Metrics.KILOMETERS));
nearQuery.query(query);
nearQuery.spherical(true); // if using 2dsphere index, otherwise delete or set false
nearQuery.num(10);
// Problem occurs here, in mapping part...
GeoResults<Mill> results = millDAO.getMongoOperations().geoNear(nearQuery, Mill.class);
System.out.println("results : " + results.getContent().size());
if (results.getContent().isEmpty()) {
basicResponse.setErrorCode(ErrorCode.FORBIDDEN_ERROR);
basicResponse.setResponse("No Crop Found for this region.");
return null;
}
List<GeoResult<Mill>> geoResults = results.getContent();
// add nearBy Mills and return this list...
List<Mill> nearByMills = new ArrayList<>();
for (GeoResult<Mill> result : geoResults) {
Mill mill = result.getContent();
nearByMills.add(mill);
}
return nearByMills;
}
This is my Mill Entity.
public class Mill extends AbstractEntity {
private String vendorId;
private String name;
private String emailAddress;
private String countryCode;
private String phoneNumber;
private String postalAddress;
#GeoSpatialIndexed(type = GeoSpatialIndexType.GEO_2DSPHERE)
private GeoJsonPoint millLocation;
private String ginningCapacity;
private String storageCapacity;
private ArrayList<MillCropRequired> millCropRequired;
public String getVendorId() {
return vendorId;
}
public void setVendorId(String vendorId) {
this.vendorId = vendorId;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public String getEmailAddress() {
return emailAddress;
}
public void setEmailAddress(String emailAddress) {
this.emailAddress = emailAddress;
}
public String getCountryCode() {
return countryCode;
}
public void setCountryCode(String countryCode) {
this.countryCode = countryCode;
}
public String getPhoneNumber() {
return phoneNumber;
}
public void setPhoneNumber(String phoneNumber) {
this.phoneNumber = phoneNumber;
}
public String getPostalAddress() {
return postalAddress;
}
public void setPostalAddress(String postalAddress) {
this.postalAddress = postalAddress;
}
public GeoJsonPoint getMillLocation() {
return millLocation;
}
public void setMillLocation(GeoJsonPoint millLocation) {
this.millLocation = millLocation;
}
public String getGinningCapacity() {
return ginningCapacity;
}
public void setGinningCapacity(String ginningCapacity) {
this.ginningCapacity = ginningCapacity;
}
public ArrayList<MillCropRequired> getCropRequirnment() {
return millCropRequired;
}
public void setCropRequirnment(ArrayList<MillCropRequired> millCropRequired) {
this.millCropRequired = millCropRequired;
}
public String getStorageCapacity() {
return storageCapacity;
}
public void setStorageCapacity(String storageCapacity) {
this.storageCapacity = storageCapacity;
}
public static class Constants extends AbstractEntity.Constants {
public static final String PHONE_NUMBER = "phoneNumber";
public static final String VENDOR_ID = "vendorId";
public static final String MILL_CROP_REQUIRED = "millCropRequired";
public static final String MILL_LOCATION = "millLocation";
}
}