public class UserDiffCallback extends DiffUtil.Callback {
    protected User[] oldList, newList;

    public UserDiffCallback(User[] oldList, User[] newList) {
        this.oldList = oldList;
        this.newList = newList;
    }

    @Override
    public int getOldListSize() {
        return oldList == null ? 0 : oldList.length;
    }

    @Override
    public int getNewListSize() {
        return newList == null ? 0 : newList.length;
    }

    @Override
    public boolean areItemsTheSame(int oldItemPosition, int newItemPosition) {
        return oldList[oldItemPosition].equals(newList[newItemPosition]);
    }

    @Override
    public boolean areContentsTheSame(int oldItemPosition, int newItemPosition) {
        return true;
    }
}

public void updateData(List<AllUsers> data) {
    // DiffUtils callbacks for calculating difference between new batch of data and old data
    // So we can update only specific views rather that updating whole list with
    // notifyDataSetChanged()
    DiffUtil.DiffResult diffResult =
            DiffUtil.calculateDiff(new UserDiffCallback(mData, data));
    mData.clear();
    mData.addAll(data);
    diffResult.dispatchUpdatesTo(this);
}