I use this:
/**
*
* @param datePicker
* @return a java.util.Date
*/
public static java.util.Date getDateFromDatePicker(DatePicker datePicker){
int day = datePicker.getDayOfMonth();
int month = datePicker.getMonth();
int year = datePicker.getYear();
Calendar calendar = Calendar.getInstance();
calendar.set(year, month, day);
return calendar.getTime();
}