Split a couple of dates in smaller chunks

I have 2 dates:

public static Date getStartDate() {
		Calendar instance = Calendar.getInstance();
		instance.set(Calendar.YEAR, 2020);
		instance.set(Calendar.MONTH, 7);
		instance.set(Calendar.DAY_OF_MONTH, 7);
		instance.set(Calendar.HOUR_OF_DAY, 9);
		instance.set(Calendar.MINUTE, 50);
		return instance.getTime();
	}

	public static Date getEndDate() {
		Calendar instance = Calendar.getInstance();
		instance.set(Calendar.YEAR, 2020);
		instance.set(Calendar.MONTH, 7);
		instance.set(Calendar.DAY_OF_MONTH, 11);
		instance.set(Calendar.HOUR_OF_DAY, 9);
		instance.set(Calendar.MINUTE, 46);
		return instance.getTime();
	}

I have the limitation that if start and end is more than an hour the process will fail, so if i have a big time frame as the previous one i need to split it in smaller chunks not bigger than an hour.

Is there an api that can divide the given start and end time to a list of smaller periods ?

Thanks.

There is no built-in method, but you can easily write yourself. This constructs a list of java.time.Instant objects that are one hour apart, starting from your start date and ending just before your end date:

    Instant start = getStartDate().toInstant();
    Instant endExclusive = getEndDate().toInstant();
    ArrayList<Instant> chunks = new ArrayList<>();

    Instant chunkStart = start;
    while (chunkStart.isBefore(endExclusive)) {
        chunks.add(chunkStart);
        chunkStart = chunkStart.plus(1, ChronoUnit.HOURS);
    }

Note that the end date here is exclusive: it's never added to the chunks list.