question: public static Calendar reduceCalendar ( Calendar calendar ) { calendar . set ( Calendar . MILLISECOND , 0 ) ; calendar . set ( Calendar . SECOND , 0 ) ; calendar . set ( Calendar . MINUTE , 0 ) ; calendar . set ( Calendar . HOUR , 0 ) ; calendar . set ( Calendar . HOUR_OF_DAY , 0 ) ; return calendar ; }
target:  sets the supplied calendar object with 0 values for fields lower than days