There's too much code here. Too much user interaction.
Start with a simple method to do one thing, then work your way out after you get that right.
Here's how you might do it:
public class DateUtils {
private DateUtils() {}
public static Date addDays(Date baseDate, int daysToAdd) {
Calendar calendar = Calendar.getInstance();
calendar.setTime(baseDate);
calendar.add(Calendar.DAY_OF_YEAR, daysToAdd);
return calendar.getTime();
}
}
Once you have this method tested and proven you can let the rest of you code just call it.
UPDATE: It's four years later, and JDK 8 has given us the new JODA-based time package. You should be using those classes, not the JDK 1.0 Calendar
.