74. Getting the first and last day of a quarter

Let’s assume that we represent the first and last day of a quarter via this simple class:

public final class Quarter { private final Date firstDay; private final Date lastDay; ... } 

Next, we have a java.util.Date and we want the first and the last day of the quarter containing this date. For this, we can use JDK 8’s IsoFields.DAY_OF_QUARTER (we introduced IsoFields in the previous problem). But, before we can use IsoFields, we have to convert the given java.util.Date to a LocalDate as follows:

LocalDate localDate = date.toInstant() .atZone(ZoneId.systemDefault()).toLocalDate(); 

Once we have the given Date as a LocalDate, we can easily extract the first day of the quarter via IsoFields.DAY_OF_QUARTER. Next, we add 2 months to this day to move into the last month of the quarter (a quarter has 3 months, so a year has 4 quarters) and we rely on java.time.temporal.TemporalAdjusters, more precisely on...