LocalTime

// ── LocalTime — purely a position on the 24-hour clock, no date attached
LocalTime openingTime = LocalTime.of(9, 0);          // 09:00 — hour, minute only
LocalTime preciseTime = LocalTime.of(14, 30, 15, 500_000_000);  // 14:30:15.500

// LocalTime is meant for RECURRING times — the same value, many different dates:
LocalTime storeOpens = LocalTime.of(9, 0);
// applies equally to today, tomorrow, and every day the store is open

// ── now() — reads the current time-of-day, zone-dependent like LocalDate.now()
LocalTime currentTime = LocalTime.now();
LocalTime currentInTokyo = LocalTime.now(ZoneId.of("Asia/Tokyo"));

// ── NOT for elapsed time/duration — that's a different job entirely ──
// LocalTime taskLength = ???   // WRONG — a length of time is not a clock position
Duration taskLength = Duration.ofMinutes(45);   // CORRECT type for "how long"

// ── Parsing — ISO-8601 by default, custom formatter otherwise ────────
LocalTime parsed = LocalTime.parse("14:30:15");          // default format
LocalTime parsedFraction = LocalTime.parse("14:30:15.250");  // fractional seconds OK

DateTimeFormatter twelveHour = DateTimeFormatter.ofPattern("hh:mm a");
LocalTime fromTwelveHour = LocalTime.parse("02:30 PM", twelveHour);

// ── Formatting back out, using the same formatter ─────────────────────
String display = LocalTime.of(14, 30).format(twelveHour);   // "02:30 PM"

// ── Unspecified fields default to ZERO, not "unset" ───────────────────
LocalTime short1 = LocalTime.of(9, 0);              // implicitly 09:00:00.000000000
LocalTime explicit = LocalTime.of(9, 0, 0, 0);
System.out.println(short1.equals(explicit));   // true — same underlying fields

// ── plusHours/minusHours wrap around midnight — there's no "next day" ─
LocalTime late = LocalTime.of(23, 0);
LocalTime wrapped = late.plusHours(2);
System.out.println(wrapped);   // 01:00 — NOT "tomorrow 01:00", just wraps to 01:00

// ── Duration.between on plain LocalTime across midnight is WRONG/negative
LocalTime start = LocalTime.of(23, 0);
LocalTime end = LocalTime.of(1, 0);
Duration wrongDuration = Duration.between(start, end);
System.out.println(wrongDuration.toMinutes());   // -1320 — treated as SAME day, goes backward!

// ── CORRECT — attach actual dates first, then measure across the boundary
LocalDateTime startDateTime = LocalDateTime.of(2024, 6, 15, 23, 0);
LocalDateTime endDateTime = LocalDateTime.of(2024, 6, 16, 1, 0);   // explicitly next day
Duration correctDuration = Duration.between(startDateTime, endDateTime);
System.out.println(correctDuration.toMinutes());   // 120 — correct, two hours elapsed