First and Last Day of Week, Month or Year in Java
Get the first and last day of week, month or year in Java with TemporalAdjusters, WeekFields for locales, YearMonth and quarter boundaries.
Calculate Number of Weeks Between Two Dates in Java
Calculate the weeks between two dates in Java with ChronoUnit.WEEKS.between(), get leftover days, round up started weeks and count calendar weeks.
Get the Day Name From a Date in Java (Localized)
Get the day name from a date in Java with getDisplayName() and TextStyle, print it in any language, list all names and parse names back.
Split a Date-Time Range into Equal Intervals in Java
Split a date-time range into equal intervals in Java, cut fixed-length chunks, or split by days, weeks, months and years with half-open ranges and DST.
Java StopWatch: Guava, Apache Commons, Spring and java.time
Java StopWatch examples with Guava Stopwatch, Commons Lang and Spring StopWatch, plus a small testable java.time version that records named laps.
Get Elapsed Time Since Midnight in Java (Seconds, Millis)
Get the elapsed time since midnight in Java in seconds or milliseconds with LocalTime, in any time zone, correct on daylight saving days.
Get the Quarter From a Date in Java, Start and End Dates
Learn to get the quarter from a date in Java with IsoFields, find quarter start and end dates, format Q3 labels and calculate fiscal quarters.
Java ZoneId and ZoneOffset: List of Zone IDs and Examples
Learn Java ZoneId and ZoneOffset with examples. Create zones with ZoneId.of(), list all zone IDs, convert a ZoneId to a ZoneOffset at an instant, handle ZoneRulesException and use ZoneId.SHORT_IDS.
Convert Instant to ZonedDateTime in Java (atZone, ofInstant)
Convert an Instant to ZonedDateTime in Java with atZone() or ofInstant(), choose the right zone, convert back with toInstant() and avoid date shifts.
Convert Instant to LocalDateTime in Java (LocalDate, LocalTime)
Convert Instant to LocalDateTime in Java with LocalDateTime.ofInstant(instant, zone). Get LocalDate or LocalTime, pick the right zone, and convert back.
Jackson – Serialize and Deserialize Dates
By default, Jackson serializes the Dates in numeric format. Learn to customize the serialization and deserialization of date and time types in Java using Jackson.
Add or Subtract Hours, Minutes and Seconds in Java
Add or subtract hours, minutes and seconds in Java with LocalDateTime, ZonedDateTime, Instant and Duration, including DST changes and midnight rollover.
How to Set the JVM Default Time Zone (TZ, -Duser.timezone)
Set the JVM default time zone with -Duser.timezone, TZ or TimeZone.setDefault(). Learn the precedence, the GMT fallback and Docker and Kubernetes setup.
Get the Day of Week From a Date in Java (DayOfWeek)
Get the day of week from a date in Java with getDayOfWeek(), read its number, handle time zones and strings, and convert java.util.Date values.
Start and End of Day in Java: atStartOfDay and LocalTime.MAX
Get the start and end of day in Java with atStartOfDay(zone) and LocalTime.MAX, handle days that skip midnight and select a day with a half-open range.
ZonedDateTime vs OffsetDateTime in Java: Key Differences
ZonedDateTime vs OffsetDateTime in Java. See how each handles DST, which one to store in a database or send in JSON, and how to convert between them.
Format Milliseconds to hh:mm:ss in Java (Duration Examples)
Format milliseconds as hours, minutes and seconds text in Java with Duration toHours() and toMinutesPart(), with days, negatives and DurationFormatUtils.
Localized Date Format in Java with Locale and Time Zone
Localized date format in Java with DateTimeFormatter, FormatStyle and Locale. Show timestamps in the user’s time zone and use ofLocalizedPattern().
Check if a Date Is a Weekend in Java
Check if a date is a weekend in Java with DayOfWeek and EnumSet, support Friday-Saturday weekends, time zones and weekend pricing examples.
Java Period Class: Years, Months and Days in java.time
Learn the Java Period class to create, parse, read and add years, months and days, with normalized(), month-end rules and Period vs Duration examples.
Java TemporalAdjusters: Built-in and Custom Date Adjusters
Java TemporalAdjusters examples for month ends, next weekdays and the second Tuesday, plus custom adjusters for working days, paydays and anniversaries.
Format a Date to String in Java: DateTimeFormatter Examples
Learn to format a date to string in Java with DateTimeFormatter, ISO constants, custom patterns and Locale, plus Instant, legacy Date and pattern mistakes.
Check If a Date Is Valid in Java (Strict Parsing Examples)
Check if a date is valid in Java with LocalDate and a strict DateTimeFormatter, then add rules such as not in the past. Covers leap years and regex limits.
Get All Dates Between Two Dates in Java (datesUntil)
List all dates between two dates in Java with LocalDate.datesUntil(). Learn how to include the end date, step by weeks or months, skip weekends, and do the same in Java 8.
Days Between Two Dates in Java (ChronoUnit.DAYS.between)
Calculate the days between two dates in Java with ChronoUnit.DAYS.between() and until(), count inclusive days, handle date-times, DST and the Period trap.
Calculate Business Days Between Two Dates in Java
Count the business days between two dates in Java with datesUntil(), exclude weekends and holidays, pick an inclusive end date or use a loop-free formula.
Add Business Days in Java: Skip Weekends and Holidays
Add business days in Java by skipping weekends and holidays with LocalDate, subtract them with the same method, and support Fri-Sat weekends.
Java DayOfWeek Enum: Methods, Day Names and Examples
Learn the Java DayOfWeek enum with getValue() vs ordinal(), day names in every style, parsing text, EnumSet, week start per locale and adjusters.
Java TemporalQuery Interface with TemporalQueries Examples
Learn Java TemporalQuery with the built-in TemporalQueries, method references and custom queries for business hours and fiscal quarters, with null rules.
Next and Previous Date in Java (Tomorrow and Yesterday)
Get the next and previous date in Java with plusDays(1) and minusDays(1), plus time zones, DST, the next Monday and the next working day with LocalDate.
Parse a String to UTC Date Time in Java (Z, Offset, GMT)
Learn to parse a date-time string to UTC in Java with Instant, OffsetDateTime and ZonedDateTime. Covers strings with Z, an offset, GMT or no zone at all. Also covers RFC 1123 dates, old SimpleDateFormat code and common DateTimeParseException causes.
ResolverStyle.STRICT vs SMART vs LENIENT Date Parsing in Java
ResolverStyle.STRICT rejects dates like February 30 that SMART and LENIENT adjust. See all three styles side by side, the uuuu vs yyyy trap and fixes.
Compare LocalDateTime in Java: isBefore, isEqual, compareTo
Compare LocalDateTime in Java with isBefore(), isAfter(), isEqual() and compareTo(), ignore seconds with truncatedTo() and handle values from other zones.
Compare LocalDate in Java: isBefore, isAfter, compareTo
Compare LocalDate values in Java with isBefore(), isAfter(), isEqual(), equals() and compareTo(), with the values compareTo() returns and a booking check.
Java 12-Hour Format With AM/PM (hh:mm a Examples)
Show time in Java 12-hour format with AM/PM using the pattern letters h and a, fix pm vs PM locale output, and convert between 12 and 24 hours.
Format LocalDate to String in Java (with Examples)
Java examples to format a LocalDate to String with toString(), DateTimeFormatter.ofPattern(), the ISO constants and localized FormatStyle with Locale, and to parse the String back.
Check Leap Year in Java With Year.isLeap()
Check leap year in Java with Year.isLeap() and LocalDate.isLeapYear(), learn the 4, 100 and 400 rule, and handle February 29 in date math.
Compare ZonedDateTime in Java: isEqual vs equals vs compareTo
Compare ZonedDateTime in Java by instant with isEqual(), see why equals() and compareTo() differ across zones, and handle DST gaps and overlaps.
Format ZonedDateTime to String in Java (Patterns and Zones)
Format ZonedDateTime to String in Java with ISO constants, zone letters z, VV and XXX, localized styles, and the same moment shown in other time zones.
Convert LocalDate to ZonedDateTime and Back in Java
Convert LocalDate to ZonedDateTime in Java with atStartOfDay(zone) or atTime().atZone(), and back with toLocalDate(), including DST days and zone pitfalls.
Convert LocalDate to LocalDateTime in Java and Back
Convert LocalDate to LocalDateTime in Java with atStartOfDay() and atTime(), and back with toLocalDate(), plus zone-aware day starts and day ranges.
Parse String to ZonedDateTime in Java (ISO, Patterns, Zones)
Parse String to ZonedDateTime in Java with ISO text, VV and XXX patterns, ambiguous names like PST or IST, and strings that have no time zone.
Convert String to LocalDateTime in Java (Patterns, Errors)
Convert a string to LocalDateTime with LocalDateTime.parse() and DateTimeFormatter. Learn the ISO format, pattern letters, AM/PM and Locale, strings with a zone, date-only strings, strict parsing and common error messages.
Convert String to LocalDate in Java: Patterns, Locales, Errors
Convert String to LocalDate in Java with LocalDate.parse(), custom patterns, month names in any locale and safe DateTimeParseException handling.
Java ZonedDateTime: Time Zones, DST and Zone Conversion
Java ZonedDateTime examples on Java 25. Create, parse and format zoned date-times, handle DST gaps and overlaps, and convert a time between zones.
Java LocalDateTime: Date and Time Without a Time Zone
Java LocalDateTime examples on Java 25. Create, parse and format date-times, add hours, compare values and convert to ZonedDateTime without DST surprises.
Java LocalTime: Time of Day Without a Date (With Examples)
Java LocalTime examples on Java 25. Create, parse and format times, add hours across midnight, check opening hours and measure the time between two times.
Java LocalDate: Create, Parse, Format and Compare Dates
Java LocalDate examples on Java 25. Create, parse and format dates, add days and months, compare dates and convert LocalDate to other date types.
Java DateTimeFormatter: Patterns, Parsing and Examples
Java DateTimeFormatter examples for formatting and parsing LocalDate, LocalDateTime and ZonedDateTime with ofPattern() letters, ISO constants, FormatStyle and Locale, plus DateTimeParseException handling and the yyyy vs YYYY mistake.
LocalDate to java.sql.Date in Java (and When to Skip It)
Convert LocalDate to java.sql.Date and LocalTime to java.sql.Time, or skip both with JDBC 4.2 setObject() and getObject(), JPA and Hibernate.