Why can't i get the correct DAY_OF_WEEK given year, month and day

Question

public String getPayrollRange(String whichhalf) throws SQLException{
int month_today = today.get(Calendar.MONTH) + 1;
int year_today = today.get(Calendar.YEAR);
int day_today = today.get(Calendar.DAY_OF_MONTH);
int end_day = 0;
int dayofweek = 0;
try{ connect();
str = "SELECT value FROM DEFAULTS WHERE variable LIKE '"+whichhalf+"%cutoff'";
rs = execSQL(str);
if(rs!=null)
{ if(rs.next())
end_day = rs.getInt("value");
rs.close();
dbCon.close();
//--------------- THIS IS THE MOST IMPT PART -----------------------
// i need to be able to set a Calendar object based on the integer variables
// my problem is when i retrieve the DAY_OF_WEEK for the given_date variable
Calendar given_date = new GregorianCalendar(year_today, month_today, 28);
str = given_date.toString();
}catch(Exception e) {
e.printStackTrace();
return str;
}

Answer 1

http://developer.java.sun.com/developer/qow/archive/152
index.jsphi! the link was a great help but 'now' refers to the current date.
my problem really is when a user specifies a given date and i'd like to get its DAY_OF_WEEK. i don't wanna use sql to get the DAYNAME.
pls help!