public static Date dayTo12AM( Date date ) {
        Calendar c = new GregorianCalendar();
        c.setTime( date );
        c.set( Calendar.HOUR_OF_DAY, 0 );
        c.set( Calendar.MINUTE, 0 );
        c.set( Calendar.SECOND, 0 );
        c.set( Calendar.MILLISECOND, 0 );
        return c.getTime();
    }