Java: Class data members which are instances of other classes are not set when instantiating

Question

I am developing an Android App, and I have a basic Customer class, which has a nationality data member which in turn is another public class. When I instantiate a new Customer both the nationality and birth date members (of non-primitive data types) are not set (calling their getters causes a null reference exception).

BTW, I'm using Android Studio, and I'm creating a new Customer instance through a JSON wrapper that receives the data from a RESTFUL web service call.

public class Customer
{
    // Private fields
    private int Id;
    private String FirstName;
    private String LastName;
    private String OfficeNumber;
    private String MobileNumber;
    private String EmailAddress;
    private boolean Gender;
    private Date BirthDate;
    private Nationality Nationality;

    /* Setters & Getters */
    public int getId() {
        return Id;
    }
    public void setId(int id) {
        Id = id;
    }

    public String getFirstName() {
        return FirstName;
    }
    public void setFirstName(String firstName) {
        FirstName = firstName;
    }

    public String getLastName() {
        return LastName;
    }
    public void setLastName(String lastName) {
        LastName = lastName;
    }

    public String getOfficeNumber() {
        return OfficeNumber;
    }
    public void setOfficeNumber(String officeNumber) {
        OfficeNumber = officeNumber;
    }

    public String getMobileNumber() {
        return MobileNumber;
    }
    public void setMobileNumber(String mobileNumber) {
        MobileNumber = mobileNumber;
    }

    public String getEmailAddress() {
        return EmailAddress;
    }
    public void setEmailAddress(String emailAddress) {
        EmailAddress = emailAddress;
    }

    public boolean getGender() {
        return Gender;
    }
    public void setGender(boolean gender) {
        Gender = gender;
    }

    public Date getBirthDate() {
        return BirthDate;
    }
    public void setBirthDate(Date birthDate) {
        BirthDate = birthDate;
    }

    public Nationality getNationality() {
        return Nationality;
    }
    public void setNationality(Nationality nationality) {Nationality = nationality; }
}

Nationality Class

public class Nationality
{
    // Private Fields
    private int Id;
    private String NationalityEn;
    private String NationalityAr;

    public Nationality(int id, String nationalityEn, String nationalityAr)
    {
        setId(id);
        setNationalityEn(nationalityEn);
        setNationalityAr(nationalityAr);
    }

    public Nationality(){}

    // Setters & Getters
    public int getId() {
        return Id;
    }

    public void setId(int id) {
        Id = id;
    }

    public String getNationalityEn() {
        return NationalityEn;
    }

    public void setNationalityEn(String nationalityEn) {
        NationalityEn = nationalityEn;
    }

    public String getNationalityAr() {
        return NationalityAr;
    }

    public void setNationalityAr(String nationalityAr) {
        NationalityAr = nationalityAr;
    }
}

Wrapper:

public class JSONToObjectWarpper
{
    public Customer getCustomerObject(JSONObject jsonObject)
    {
        Customer customer = new Customer();

        try
        {
            JSONObject js = jsonObject.getJSONObject("Customer");
            Nationality nationality = new Nationality(
                    js.getJSONObject("Nationality").getInt("Id"),
                    js.getJSONObject("Nationality").getString("NationalityEn"),
                    js.getJSONObject("Nationality").getString("NationalityAr")
            );
            Date date = ConvertFromWCFDate(js.getString("BirthDate"));

            customer.setId(js.getInt("Id"));
            customer.setFirstName(js.getString("FirstName"));
            customer.setLastName(js.getString("LastName"));
            customer.setOfficeNumber(js.getString("OfficeNumber"));
            customer.setMobileNumber(js.getString("MobileNumber"));
            customer.setEmailAddress(js.getString("EmailAddress"));
            customer.setGender(js.getBoolean("Gender"));
            customer.setBirthDate(date);
            customer.setNationality(nationality);

        }
        catch (JSONException e)
        {
            // Handle the Exception Here
        }
        return customer;
    }
}

What am I missing here ?! Thanks in advance for the help.

Answer 1

Handle the exception in the catch block and print the exception stack to see exactly what is going on and where exactly the exception is coming from. Also, print your JSON object to make sure the data is actually received and your are getting the right properties.