same day I found solution, but was little busy, So to get Current Date b'days instead of using today's date in logic, i am using yesterday's date, i did some changes in my code, see below:
Calendar cal = Calendar.getInstance();
Date today = cal.getTime();
Date oneDayBefore = new Date(today.getTime() - 10);
SimpleDateFormat formatter = new SimpleDateFormat("MM/dd");
String today_formatted = formatter.format(oneDayBefore);
String query = "select name, birthday, uid, pic_square FROM user " +
"WHERE uid in (SELECT uid2 FROM friend WHERE uid1 = me()) AND birthday_date != 'null' " +
"AND birthday_date > '" + today_formatted + "'ORDER BY birthday_date ASC";
by using above code you can get current date b'days along with all upcoming facebook friend's birthdays or even more just use >= this in place of > to get past day birthday(s) of your friend(s)