Error in the Dates in java.util.Calendar/java.util.SimpleDateFormat

Question

I specifies the year(1999) and the week of that year(1).
Then I want an existing date like 1999-01-01.
But I get 1998-12-31. This date is WEEK 53 of year 1998.
So what I found was that every week in a year (Ex. 1999),
that have a previous year with 53 weeks (Ex. 1998), have
their dates dislocated one week. This means that
all dates I receive is from the previous week instead for
the correct one.
Code ex.
Calendar aCalendar=Calendar.getInstance();
aCalendar.set(Calendar.YEAR, aIntYear);
aCalendar.set(Calendar.WEEK_OF_YEAR, aIntWeek);
SimpleDateFormat aDateFormatter=new SimpleDateFormat ("yyyy-MM-dd");
aDateFormatter.setCalendar(aCalendar);
String aParsedDate=aDateFormatter.format(aCalendar.getTime());
Have anyone a good solution for this, (without a check if the previous year
has 53 weeks and then adding 1 to all weeks in the next year)?

Answer 1

After reading the API I see that their implementation is correct. If the first day of the year doesn't begin on the first day of the week, then the first day of that week is in the previous year.
For example if New Year's day is on Wednesday and the first day of that week is Sunday then the date of the first day of the week (Sunday) is in the previous year.
I'm not sure how you would like to alter this, if you change it so that it ignores that the first week was not 7 days long then your program will return incorrect values. In the previous example, your proposed alteration would return January 5 as the first day of the first week of the year, which doesn't make any sense.
One thing you could do is check to see that after you set the week, check to see whether the date returned is less than the first day of the year you set. If so return the first day of the year.