Android - Remove Duplicate Contacts

I am trying to display contacts in Recycler View everything is working fine but contacts are getting displayed twice or thrice.

Here is the Code

 RecyclerView recyclerView;
 List<Contacts> contactsList;
 ContactsAdapter adapter;

 public void getContactList() {
    Cursor cursor = getContentResolver().query(ContactsContract.CommonDataKinds.Phone.CONTENT_URI,
            null, null, null,
            "UPPER(" + ContactsContract.Contacts.DISPLAY_NAME + ") ASC");
    while (cursor.moveToNext()) {
        String name = cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.DISPLAY_NAME));
        String number = cursor.getString(cursor.getColumnIndex(ContactsContract.CommonDataKinds.Phone.NUMBER));

        Contacts contacts = new Contacts(name, number);
        if (contactsList.contains(contacts)){
            cursor.moveToNext();
        }
        else {
            contactsList.add(contacts);
        }
        adapter = new ContactsAdapter(contactsList, getApplicationContext());
        recyclerView.setAdapter(adapter);

        adapter.notifyDataSetChanged();
    }
}

So, how can I solve this problem?

from Android - Remove Duplicate Contacts