Practice Test Geeks(OCP) Oracle Certified Professional Practice Test
← All OCP Flashcard Decks

Date, Time, and Localization Flashcards

7 cards from real OCP practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.

Read the first 7 Date, Time, and Localization flashcards as text

  1. Which Java class should you use to represent a single point in time as seconds since the Unix epoch?

    Answer: Instant

    Instant models a single instantaneous point on the timeline in epoch-seconds and nanosecond adjustment, independent of any time zone.

  2. What is the result of `LocalDate.of(2024, 1, 31).plusMonths(1)`?

    Answer: 2024-02-29

    Java adjusts the day to the last valid day of the target month; February 2024 has 29 days (leap year), so the result is 2024-02-29.

  3. Which expression correctly calculates the total number of days between two LocalDate instances?

    Answer: ChronoUnit.DAYS.between(date1, date2)

    ChronoUnit.DAYS.between(date1, date2) returns the total elapsed days; Period.between().getDays() only returns the day component, not the total, and Duration.between() does not accept LocalDate.

  4. How do you convert a ZonedDateTime to the same instant in a different time zone?

    Answer: zonedDateTime.withZoneSameInstant(ZoneId.of("Europe/London"))

    withZoneSameInstant() converts the ZonedDateTime to a new zone while keeping the underlying instant the same, correctly shifting the wall-clock time.

  5. What is the output of `DateTimeFormatter.ofPattern("MM/dd/uuuu").format(LocalDate.of(2024, 6, 5))`?

    Answer: "06/05/2024"

    The pattern MM pads the month to 2 digits and dd pads the day to 2 digits, so month 6 becomes "06" and day 5 becomes "05", yielding "06/05/2024".

  6. Which statement about the zone ID "US/Eastern" is correct?

    Answer: It is a valid alias for America/New_York and handles DST automatically

    "US/Eastern" is a legacy IANA alias for "America/New_York" and is fully recognized by Java's ZoneId, including DST rules.

  7. What is the key difference between ZonedDateTime and OffsetDateTime?

    Answer: ZonedDateTime includes DST rules tied to a geographic zone; OffsetDateTime stores a fixed UTC offset only

    ZonedDateTime carries full time-zone rules (including DST transitions) via a ZoneId, whereas OffsetDateTime holds only a fixed numeric offset with no DST awareness.