Java 8 Date and Time API Tutorial with Practical Code Examples

Introduction

Java 8 adds a brand‑new date‑time API that solves the mutability and thread‑safety problems of java.util.Date and SimpleDateFormat . The new API is based on ISO‑8601, provides immutable classes, and is fully thread‑safe.

Key Classes

Instant – a point on the timeline.

LocalDate – a date without time.

LocalTime – a time without date.

LocalDateTime – a date‑time without zone.

ZonedDateTime – a date‑time with zone.

ZoneId and ZoneOffset – zone information.

YearMonth , MonthDay – month‑year and month‑day combinations.

Period – date‑based amount of time.

ChronoUnit – unit‑based amount of time.

Clock – provides the current instant and time‑zone.

Practical Examples

1. Get the current date

public void getCurrentDate() {
    LocalDate today = LocalDate.now();
    System.out.println("Today's Local date : " + today);
    Date date = new Date();
    System.out.println(date);
}

2. Extract year, month, day

public void getDetailDate() {
    LocalDate today = LocalDate.now();
    int year = today.getYear();
    int month = today.getMonthValue();
    int day = today.getDayOfMonth();
    System.out.printf("Year : %d  Month : %d  Day : %d%n", year, month, day);
}

3. Create a specific date

public void handleSpecialDate() {
    LocalDate dateOfBirth = LocalDate.of(2018, 1, 21);
    System.out.println("The special date is : " + dateOfBirth);
}

4. Compare two dates

public void compareDate() {
    LocalDate today = LocalDate.now();
    LocalDate date1 = LocalDate.of(2018, 1, 21);
    if (date1.equals(today)) {
        System.out.printf("TODAY %s and DATE1 %s are same date%n", today, date1);
    }
}

5. Check recurring events (birthday)

public void cycleDate() {
    LocalDate today = LocalDate.now();
    LocalDate dateOfBirth = LocalDate.of(2018, 1, 21);
    MonthDay birthday = MonthDay.of(dateOfBirth.getMonth(), dateOfBirth.getDayOfMonth());
    MonthDay current = MonthDay.from(today);
    if (current.equals(birthday)) {
        System.out.println("Many Many happy returns of the day !!");
    } else {
        System.out.println("Sorry, today is not your birthday");
    }
}

6. Get the current time

public void getCurrentTime() {
    LocalTime time = LocalTime.now();
    System.out.println("local time now : " + time);
}

7. Add hours to a time

public void plusHours() {
    LocalTime time = LocalTime.now();
    LocalTime newTime = time.plusHours(2);
    System.out.println("Time after 2 hours : " + newTime);
}

8. Calculate a date one week later

public void nextWeek() {
    LocalDate today = LocalDate.now();
    LocalDate nextWeek = today.plus(1, ChronoUnit.WEEKS);
    System.out.println("Today is : " + today);
    System.out.println("Date after 1 week : " + nextWeek);
}

9. Add or subtract years

public void minusDate() {
    LocalDate today = LocalDate.now();
    LocalDate previousYear = today.minus(1, ChronoUnit.YEARS);
    System.out.println("Date before 1 year : " + previousYear);
    LocalDate nextYear = today.plus(1, ChronoUnit.YEARS);
    System.out.println("Date after 1 year : " + nextYear);
}

10. Use Clock for timestamps and zones

public void clock() {
    Clock utcClock = Clock.systemUTC();
    System.out.println("Clock : " + utcClock);
    Clock defaultClock = Clock.systemDefaultZone();
    System.out.println("Clock : " + defaultClock);
}

11. Compare dates with isBefore / isAfter

public void isBeforeOrIsAfter() {
    LocalDate today = LocalDate.now();
    LocalDate tomorrow = LocalDate.of(2018, 1, 29);
    if (tomorrow.isAfter(today)) {
        System.out.println("Tomorrow comes after today");
    }
    LocalDate yesterday = today.minus(1, ChronoUnit.DAYS);
    if (yesterday.isBefore(today)) {
        System.out.println("Yesterday is day before today");
    }
}

12. Work with time zones

public void getZoneTime() {
    ZoneId america = ZoneId.of("America/New_York");
    LocalDateTime local = LocalDateTime.now();
    ZonedDateTime zoned = ZonedDateTime.of(local, america);
    System.out.println("Date and time in specific zone : " + zoned);
}

13. Handle fixed‑date scenarios with YearMonth

public void checkCardExpiry() {
    YearMonth now = YearMonth.now();
    System.out.printf("Days in month %s : %d%n", now, now.lengthOfMonth());
    YearMonth creditCardExpiry = YearMonth.of(2028, Month.FEBRUARY);
    System.out.printf("Your credit card expires on %s%n", creditCardExpiry);
}

14. Determine leap years

public void isLeapYear() {
    LocalDate today = LocalDate.now();
    if (today.isLeapYear()) {
        System.out.println("This year is Leap year");
    } else {
        System.out.println("2018 is not a Leap year");
    }
}

15. Calculate months between two dates

public void calcDateDays() {
    LocalDate today = LocalDate.now();
    LocalDate java8Release = LocalDate.of(2018, Month.MAY, 14);
    Period period = Period.between(today, java8Release);
    System.out.println("Months left between today and Java 8 release : " + period.getMonths());
}

16. Date‑time with explicit offset

public void ZoneOffset() {
    LocalDateTime datetime = LocalDateTime.of(2018, Month.FEBRUARY, 14, 19, 30);
    ZoneOffset offset = ZoneOffset.of("+05:30");
    OffsetDateTime date = OffsetDateTime.of(datetime, offset);
    System.out.println("Date and Time with timezone offset in Java : " + date);
}

17. Get the current timestamp

public void getTimestamp() {
    Instant timestamp = Instant.now();
    System.out.println("What is value of this instant " + timestamp);
}

18. Format and parse dates with predefined formatters

public void formateDate() {
    String str = "20180210";
    LocalDate formatted = LocalDate.parse(str, DateTimeFormatter.BASIC_ISO_DATE);
    System.out.printf("Date generated from String %s is %s%n", str, formatted);
}

Summary

The Java 8 date‑time API provides a comprehensive, immutable, and thread‑safe set of classes for handling dates, times, periods, and zones, replacing the legacy java.util.Date and SimpleDateFormat . By using classes such as LocalDate , LocalTime , ZonedDateTime , and utilities like Clock and DateTimeFormatter , developers can write clear, concise, and reliable date‑time code.