Here i am fetching the name,email,phone number from the mobile and trying to upload to server..Here if the contacts contains name,email and phone number the values will be inserted successfully..but if any of the field is empty it is throwing NULL pointer exception.How to avoid this one..i mean if the contact does not contain email it should atleast send name and phone number.

here is my code.

```
public class DisplayContact1 extends Activity {

    private static String TAG = WorkDetails1.class.getSimpleName();

    Button select;

    private String vault;
    List<AddressBookContact> list;

    public static final String kvault = "vault_no";
    public static final String kname = "name";
    public static final String kphone = "phone";
    public static final String kemail = "email";
    public static final String kcontacts = "contacts";

    public static final String SHARED_PREF_NAME = "myloginapp";

    public static final String UPLOAD_URL = "http://oursite.com/contacts_1.php";

    private static final int MY_PERMISSIONS_REQUEST_READ_CONTACTS = 1;

    Cursor cursor;
    LongSparseArray<AddressBookContact> array;
    long start;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        //getActionBar().setDisplayShowTitleEnabled(false);
        setContentView(R.layout.display);

        SharedPreferences sharedPreferences = getSharedPreferences(ProfileLogin.SHARED_PREF_NAME, MODE_PRIVATE);

        vault = sharedPreferences.getString(ProfileLogin.EMAIL_SHARED_PREF,"Not Available");
        getAllContacts(this.getContentResolver());

    }

    public  void getAllContacts(ContentResolver cr) {

        int result = ContextCompat.checkSelfPermission(DisplayContact1.this, Manifest.permission.READ_CONTACTS);
        if (result == PackageManager.PERMISSION_GRANTED){

            //fetches contacts from the phone contact list and displays in ascending order
            list = new LinkedList<AddressBookContact>();
            array = new LongSparseArray<AddressBookContact>();
            start = System.currentTimeMillis();

            String[] projection = {
                    ContactsContract.Data.MIMETYPE,
                    ContactsContract.Data.CONTACT_ID,
                    ContactsContract.Contacts.DISPLAY_NAME,
                    ContactsContract.CommonDataKinds.Contactables.DATA,
                    ContactsContract.CommonDataKinds.Contactables.TYPE,
            };
            String selection = ContactsContract.Data.MIMETYPE + " in (?, ?)";
            String[] selectionArgs = {
                    ContactsContract.CommonDataKinds.Email.CONTENT_ITEM_TYPE,
                    ContactsContract.CommonDataKinds.Phone.CONTENT_ITEM_TYPE,
            };
            String sortOrder = ContactsContract.Contacts.SORT_KEY_ALTERNATIVE;

            Uri uri = ContactsContract.Data.CONTENT_URI;
// we could also use Uri uri = ContactsContract.Data.CONTENT_URI;

            cursor = getContentResolver().query(uri, projection, selection, selectionArgs, sortOrder);
            contactsdisplay();

        } else {

            requestForLocationPermission();
        }
    }

    private void requestForLocationPermission()
    {

        if (ActivityCompat.shouldShowRequestPermissionRationale(DisplayContact1.this, Manifest.permission.READ_CONTACTS))
        {
        }
        else {

            ActivityCompat.requestPermissions(DisplayContact1.this, new String[]{Manifest.permission.READ_CONTACTS}, MY_PERMISSIONS_REQUEST_READ_CONTACTS);
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, String permissions[], int[] grantResults)
    {
        switch (requestCode) {
            case MY_PERMISSIONS_REQUEST_READ_CONTACTS:
                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED)
                {
                    getAllContacts(DisplayContact1.this.getContentResolver());
                    contactsdisplay();
                }
                break;
        }
    }

    public  void contactsdisplay() {

        //Cursor phones = cr.query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI, null,null,null, null);
        final int mimeTypeIdx = cursor.getColumnIndex(ContactsContract.Data.MIMETYPE);
        final int idIdx = cursor.getColumnIndex(ContactsContract.Data.CONTACT_ID);
        final int nameIdx = cursor.getColumnIndex(ContactsContract.Contacts.DISPLAY_NAME);
        final int dataIdx = cursor.getColumnIndex(ContactsContract.CommonDataKinds.Contactables.DATA);
        final int typeIdx = cursor.getColumnIndex(ContactsContract.CommonDataKinds.Contactables.TYPE);

        while (cursor.moveToNext()) {
            long id = cursor.getLong(idIdx);
            AddressBookContact addressBookContact = array.get(id);
            if (addressBookContact == null) {
                addressBookContact = new AddressBookContact(id, cursor.getString(nameIdx), getResources());
                array.put(id, addressBookContact);
                list.add(addressBookContact);
            }
            int type = cursor.getInt(typeIdx);
            String data = cursor.getString(dataIdx);
            String mimeType = cursor.getString(mimeTypeIdx);
            if (mimeType.equals(ContactsContract.CommonDataKinds.Email.CONTENT_ITEM_TYPE)) {
                // mimeType == ContactsContract.CommonDataKinds.Email.CONTENT_ITEM_TYPE
                addressBookContact.addEmail(type, data);
            } else {
                // mimeType == ContactsContract.CommonDataKinds.Phone.CONTENT_ITEM_TYPE
                addressBookContact.addPhone(type, data);
            }
        }
        long ms = System.currentTimeMillis() - start;
        cursor.close();

// done!!! show the results...
        int i = 1;
        for (AddressBookContact addressBookContact : list) {
            Log.d(TAG, "AddressBookContact #" + i++ + ": " + addressBookContact.toString(true));
        }
        final String cOn = "<b><font color='#ff9900'>";
        final String cOff = "</font></b>";
        Spanned l1 = Html.fromHtml("got " + cOn + array.size() + cOff + " contacts<br/>");
        Spanned l2 = Html.fromHtml("query took " + cOn + ms / 1000f + cOff + " s (" + cOn + ms + cOff + " ms)");

        Log.d(TAG, "\n\n╔══════ query execution stats ═══════" );
        Log.d(TAG, "║    " + l1);
        Log.d(TAG, "║    " + l2);
        Log.d(TAG, "╚════════════════════════════════════" );
        SpannableStringBuilder msg = new SpannableStringBuilder().append(l1).append(l2);

        ListView lv= (ListView) findViewById(R.id.lv);
        lv.setAdapter(new ArrayAdapter<AddressBookContact>(this, android.R.layout.simple_list_item_1, list));
        lv.setItemsCanFocus(false);
        lv.setTextFilterEnabled(true);

        select = (Button) findViewById(R.id.button1);
        select.setOnClickListener(new View.OnClickListener()
        {
            @Override
            public void onClick(View v){
                uploadImage();
            }

        });
    }

    public void uploadImage(){

        SharedPreferences sharedPreferences = getSharedPreferences(DisplayContact.SHARED_PREF_NAME, MODE_PRIVATE);

        final String vault_no = vault;

        class UploadImage extends AsyncTask<Void,Void,String> {
            ProgressDialog loading;
            @Override
            protected void onPreExecute() {
                super.onPreExecute();
                loading = ProgressDialog.show(DisplayContact1.this,"Please wait...","uploading",false,false);
            }

            @Override
            protected void onPostExecute(String s) {
                super.onPostExecute(s);
                loading.dismiss();
                if(s.equalsIgnoreCase("Successfully Saved")){
                    //Intent intent = new Intent(CollegeDetails.this,Work.class);
                    Toast.makeText(DisplayContact1.this, s, Toast.LENGTH_SHORT).show();
                    // startActivity(intent);
                }else{
                    Toast.makeText(DisplayContact1.this,s,Toast.LENGTH_SHORT).show();

                }
            }

            @Override
            protected String doInBackground(Void... params) {
                RequestHandler rh = new RequestHandler();
                //RegisterUserClass rh = new RegisterUserClass();
                HashMap<String,String> param = new HashMap<String,String>();

                JSONArray contacts = new JSONArray();
                int i = 1;
                for (AddressBookContact addressBookContact : list) {
                    try {
                        Log.d(TAG, "AddressBookContact #" + i++ + ": " + addressBookContact.toString(true));
                        JSONObject contact = new JSONObject();

                        contact.put(kname, addressBookContact.name.toString());
                        contact.put(kvault, vault_no);
                        contact.put(kphone, addressBookContact.phone.toString());

                        if(addressBookContact.email.toString()!=null)
                           contact.put(kemail, addressBookContact.email.toString());

                        contacts.put(contact);
                    }
                    catch (JSONException e) {
                        // TODO Auto-generated catch block
                        e.printStackTrace();
                    }

                    param.put(kcontacts, contacts.toString());
                    System.out.println("param value.." + i++ +":"+ contacts.toString());
                }
                return rh.sendPostRequest(UPLOAD_URL, param);

            }
        }
        UploadImage u = new UploadImage();
        u.execute();
    }
}

```

here is the **AddressBookContact.class**

```
public class AddressBookContact {

    private long id;
    private Resources res;
    String name;
    LongSparseArray<String> email;
    LongSparseArray<String> phone;

    AddressBookContact(long id, String name, Resources res) {
        this.id = id;
        this.name = name;
        this.res = res;
    }

    @Override
    public String toString() {
        return toString(false);
    }

    public String toString(boolean rich) {
        SpannableStringBuilder builder = new SpannableStringBuilder();
        if (rich) {
            builder.append("id: ").append(Long.toString(id))

                    .append(", name: ").append(name);
        } else {
            builder.append("name: ").append(name);
        }

        if (phone != null) {
            builder.append("\nphone: ");
            for (int i = 0; i < phone.size(); i++) {
                int type = (int) phone.keyAt(i);

                builder.append(phone.valueAt(i));
                if (i + 1 < phone.size()) {
                    builder.append(", ");
                }
            }
        }

        if (email != null) {
            builder.append("\nemail: ");
            for (int i = 0; i < email.size(); i++) {
                int type = (int) email.keyAt(i);

                builder.append(email.valueAt(i));
                if (i + 1 < email.size()) {
                    builder.append(", ");
                }
            }
        }
        return builder.toString();
    }

    public void addEmail(int type, String address) {
        if (email == null) {
            email = new LongSparseArray<String>();
        }
        email.put(type, address);
    }

    public void addPhone(int type, String number) {
        if (phone == null) {
            phone = new LongSparseArray<String>();
        }
        phone.put(type, number);
    }
}

```

if email field is empty, i am getting null pointer exception at this line..
`contact.put(kemail, addressBookContact.email.toString());`..so i have added if loop to check the null condition..but then also i am getting exception.