Get next Sunday

import java.util.Calendar;
import java.util.Date;

public class Main {
  public static void main(String[] argv) {
    System.out.println(getSunday(new Date()));
  }

  public static Date getSunday(Date today) {
    Calendar cal = Calendar.getInstance();

    cal.setTime(today);

    int dow = cal.get(Calendar.DAY_OF_WEEK);

    while (dow != Calendar.SUNDAY) {
      int date = cal.get(Calendar.DATE);

      int month = cal.get(Calendar.MONTH);

      int year = cal.get(Calendar.YEAR);

      if (date == getMonthLastDate(month, year)) {

        if (month == Calendar.DECEMBER) {
          month = Calendar.JANUARY;

          cal.set(Calendar.YEAR, year + 1);
        } else {
          month++;
        }

        cal.set(Calendar.MONTH, month);

        date = 1;
      } else {
        date++;
      }

      cal.set(Calendar.DATE, date);

      dow = cal.get(Calendar.DAY_OF_WEEK);
    }

    return cal.getTime();
  }

  private static int getMonthLastDate(int month, int year) {
    switch (month) {
    case Calendar.JANUARY:
    case Calendar.MARCH:
    case Calendar.MAY:
    case Calendar.JULY:
    case Calendar.AUGUST:
    case Calendar.OCTOBER:
    case Calendar.DECEMBER:
      return 31;

    case Calendar.APRIL:
    case Calendar.JUNE:
    case Calendar.SEPTEMBER:
    case Calendar.NOVEMBER:
      return 30;

    default: // Calendar.FEBRUARY
      return year % 4 == 0 ? 29 : 28;
    }
  }
}