Date & Time

LocalDate Introduction

When tracking birthdays, deadlines, or scheduling events, you need to work with calendar dates. LocalDate provides a clean API for date manipulation without the complexity of time zones, replacing the error-prone legacy Date class.

LocalDate represents a date without time in the ISO calendar system (year-month-day). It's part of the java.time package introduced in Java 8.

Getting Current Date

Current.java
Replay: real traced execution (multi-file project)
// Current date

import java.time.LocalDate;

public class Current {

    public static void main(String[] args) {
        // Static replay uses a fixed sample "today".
        LocalDate today = LocalDate.of(2025, 1, 29);
        System.out.println("Sample today: " + today);

        // Date components
        int year = today.getYear();
        int month = today.getMonthValue();
        int day = today.getDayOfMonth();

        System.out.println("\nDate components:");
        System.out.println("Year: " + year);
        System.out.println("Month: " + month);
        System.out.println("Day: " + day);

        // Day of week
        System.out.println("Day of week: " + today.getDayOfWeek());

        // Day of year
        System.out.println("Day of year: " + today.getDayOfYear());

        // Month name
        System.out.println("Month name: " + today.getMonth());

        // Is leap year
        System.out.println("Leap year: " + today.isLeapYear());

        // Length of month
        System.out.println("Days in month: " + today.lengthOfMonth());

        // Length of year
        System.out.println("Days in year: " + today.lengthOfYear());
    }

}

  1. today ← 2025-01-29, year ← 2025, month ← 1, day ← 29

    7public static void main(String[] args) {8    // Static replay uses a fixed sample "today".9    LocalDate today→ 2025-01-29 = LocalDate.of(2025, 1, 29);10    System.out.println("Sample today: " + today2025-01-29);1112    // Date components13    int year→ 2025 = today.getYear();14    int month→ 1 = today.getMonthValue();15    int day→ 29 = today.getDayOfMonth();1617    System.out.println("\nDate components:");18    System.out.println("Year: " + year2025);19    System.out.println("Month: " + month1);20    System.out.println("Day: " + day29);2122    // Day of week23    System.out.println("Day of week: " + today.getDayOfWeek());2425    // Day of year26    System.out.println("Day of year: " + today.getDayOfYear());2728    // Month name29    System.out.println("Month name: " + today.getMonth());3031    // Is leap year32    System.out.println("Leap year: " + today.isLeapYear());3334    // Length of month35    System.out.println("Days in month: " + today.lengthOfMonth());3637    // Length of year38    System.out.println("Days in year: " + today.lengthOfYear());39}
    outputSample today: 2025-01-29

Date components:
Year: 2025
Month: 1
Day: 29
Day of week: WEDNESDAY
Day of year: 29
Month name: JANUARY
Leap year: false
Days in month: 31
Days in year: 365
LocalDate An immutable date object representing year, month, and day without time or timezone information.

Creating Specific Dates

date1
Create.java
Replay: real traced execution (multi-file project)
// Create specific date

import java.time.LocalDate;
import java.time.Month;

public class Create {

    public static void main(String[] args) {
        // Create with year, month, day
        LocalDate date1 = LocalDate.of(2025, 1, 29);
        System.out.println("Date 1: " + date1);

        // Create with Month enum
        LocalDate date2 = LocalDate.of(2025, Month.JANUARY, 29);
        System.out.println("Date 2: " + date2);

        // Special dates
        LocalDate newYear = LocalDate.of(2025, 1, 1);
        System.out.println("\nNew Year 2025: " + newYear);

        LocalDate christmas = LocalDate.of(2025, 12, 25);
        System.out.println("Christmas 2025: " + christmas);

        // First day of month
        LocalDate today = LocalDate.of(2025, 1, 29);
        LocalDate firstOfMonth = today.withDayOfMonth(1);
        System.out.println("\nFirst of this month: " + firstOfMonth);

        // Last day of month
        LocalDate lastOfMonth = today.withDayOfMonth(today.lengthOfMonth());
        System.out.println("Last of this month: " + lastOfMonth);

        // First day of year
        LocalDate firstOfYear = today.withDayOfYear(1);
        System.out.println("First of this year: " + firstOfYear);

        // Change components
        LocalDate modified = date1.withYear(2026).withMonth(6).withDayOfMonth(15);
        System.out.println("\nModified date: " + modified);

        // Min and max dates
        LocalDate min = LocalDate.MIN;
        LocalDate max = LocalDate.MAX;
        System.out.println("\nMin date: " + min);
        System.out.println("Max date: " + max);

        // Epoch (1970-01-01)
        LocalDate epoch = LocalDate.ofEpochDay(0);
        System.out.println("Epoch: " + epoch);
    }

}

// Create specific date

import java.time.LocalDate;
import java.time.Month;

public class Create {

    public static void main(String[] args) {
        // Create with year, month, day
        LocalDate date1 = LocalDate.of(2024, 2, 29);
        System.out.println("Date 1: " + date1);

        // Create with Month enum
        LocalDate date2 = LocalDate.of(2025, Month.JANUARY, 29);
        System.out.println("Date 2: " + date2);

        // Special dates
        LocalDate newYear = LocalDate.of(2025, 1, 1);
        System.out.println("\nNew Year 2025: " + newYear);

        LocalDate christmas = LocalDate.of(2025, 12, 25);
        System.out.println("Christmas 2025: " + christmas);

        // First day of month
        LocalDate today = LocalDate.of(2025, 1, 29);
        LocalDate firstOfMonth = today.withDayOfMonth(1);
        System.out.println("\nFirst of this month: " + firstOfMonth);

        // Last day of month
        LocalDate lastOfMonth = today.withDayOfMonth(today.lengthOfMonth());
        System.out.println("Last of this month: " + lastOfMonth);

        // First day of year
        LocalDate firstOfYear = today.withDayOfYear(1);
        System.out.println("First of this year: " + firstOfYear);

        // Change components
        LocalDate modified = date1.withYear(2026).withMonth(6).withDayOfMonth(15);
        System.out.println("\nModified date: " + modified);

        // Min and max dates
        LocalDate min = LocalDate.MIN;
        LocalDate max = LocalDate.MAX;
        System.out.println("\nMin date: " + min);
        System.out.println("Max date: " + max);

        // Epoch (1970-01-01)
        LocalDate epoch = LocalDate.ofEpochDay(0);
        System.out.println("Epoch: " + epoch);
    }

}

  1. date1 ← 2025-01-29, date2 ← 2025-01-29, newYear ← 2025-01-01, christmas ← 2025-12-25

    8public static void main(String[] args) {9    // Create with year, month, day10    LocalDate date1→ 2025-01-29 = LocalDate.of(2025, 1, 29); //@date1=LocalDate.of(2025, 1, 29), LocalDate.of(2024, 2, 29)11    System.out.println("Date 1: " + date12025-01-29);1213    // Create with Month enum14    LocalDate date2→ 2025-01-29 = LocalDate.of(2025, Month.JANUARY, 29);15    System.out.println("Date 2: " + date22025-01-29);1617    // Special dates18    LocalDate newYear→ 2025-01-01 = LocalDate.of(2025, 1, 1);19    System.out.println("\nNew Year 2025: " + newYear2025-01-01);2021    LocalDate christmas→ 2025-12-25 = LocalDate.of(2025, 12, 25);22    System.out.println("Christmas 2025: " + christmas2025-12-25);2324    // First day of month25    LocalDate today→ 2025-01-29 = LocalDate.of(2025, 1, 29);26    LocalDate firstOfMonth→ 2025-01-01 = today.withDayOfMonth(1);27    System.out.println("\nFirst of this month: " + firstOfMonth2025-01-01);2829    // Last day of month30    LocalDate lastOfMonth→ 2025-01-31 = today.withDayOfMonth(today.lengthOfMonth());31    System.out.println("Last of this month: " + lastOfMonth2025-01-31);3233    // First day of year34    LocalDate firstOfYear→ 2025-01-01 = today.withDayOfYear(1);35    System.out.println("First of this year: " + firstOfYear2025-01-01);3637    // Change components38    LocalDate modified→ 2026-06-15 = date1.withYear(2026).withMonth(6).withDayOfMonth(15);39    System.out.println("\nModified date: " + modified2026-06-15);4041    // Min and max dates42    LocalDate min→ -999999999-01-01 = LocalDate.MIN;43    LocalDate max→ +999999999-12-31 = LocalDate.MAX;44    System.out.println("\nMin date: " + min-999999999-01-01);45    System.out.println("Max date: " + max+999999999-12-31);4647    // Epoch (1970-01-01)48    LocalDate epoch→ 1970-01-01 = LocalDate.ofEpochDay(0);49    System.out.println("Epoch: " + epoch1970-01-01);50}
    outputDate 1: 2025-01-29
Date 2: 2025-01-29

New Year 2025: 2025-01-01
Christmas 2025: 2025-12-25

First of this month: 2025-01-01
Last of this month: 2025-01-31
First of this year: 2025-01-01

Modified date: 2026-06-15

Min date: -999999999-01-01
Max date: +999999999-12-31
Epoch: 1970-01-01

  1. date1 ← 2024-02-29, date2 ← 2025-01-29, newYear ← 2025-01-01, christmas ← 2025-12-25

    8public static void main(String[] args) {9    // Create with year, month, day10    LocalDate date1→ 2024-02-29 = LocalDate.of(2024, 2, 29);11    System.out.println("Date 1: " + date12024-02-29);1213    // Create with Month enum14    LocalDate date2→ 2025-01-29 = LocalDate.of(2025, Month.JANUARY, 29);15    System.out.println("Date 2: " + date22025-01-29);1617    // Special dates18    LocalDate newYear→ 2025-01-01 = LocalDate.of(2025, 1, 1);19    System.out.println("\nNew Year 2025: " + newYear2025-01-01);2021    LocalDate christmas→ 2025-12-25 = LocalDate.of(2025, 12, 25);22    System.out.println("Christmas 2025: " + christmas2025-12-25);2324    // First day of month25    LocalDate today→ 2025-01-29 = LocalDate.of(2025, 1, 29);26    LocalDate firstOfMonth→ 2025-01-01 = today.withDayOfMonth(1);27    System.out.println("\nFirst of this month: " + firstOfMonth2025-01-01);2829    // Last day of month30    LocalDate lastOfMonth→ 2025-01-31 = today.withDayOfMonth(today.lengthOfMonth());31    System.out.println("Last of this month: " + lastOfMonth2025-01-31);3233    // First day of year34    LocalDate firstOfYear→ 2025-01-01 = today.withDayOfYear(1);35    System.out.println("First of this year: " + firstOfYear2025-01-01);3637    // Change components38    LocalDate modified→ 2026-06-15 = date1.withYear(2026).withMonth(6).withDayOfMonth(15);39    System.out.println("\nModified date: " + modified2026-06-15);4041    // Min and max dates42    LocalDate min→ -999999999-01-01 = LocalDate.MIN;43    LocalDate max→ +999999999-12-31 = LocalDate.MAX;44    System.out.println("\nMin date: " + min-999999999-01-01);45    System.out.println("Max date: " + max+999999999-12-31);4647    // Epoch (1970-01-01)48    LocalDate epoch→ 1970-01-01 = LocalDate.ofEpochDay(0);49    System.out.println("Epoch: " + epoch1970-01-01);50}
    outputDate 1: 2024-02-29
Date 2: 2025-01-29

New Year 2025: 2025-01-01
Christmas 2025: 2025-12-25

First of this month: 2025-01-01
Last of this month: 2025-01-31
First of this year: 2025-01-01

Modified date: 2026-06-15

Min date: -999999999-01-01
Max date: +999999999-12-31
Epoch: 1970-01-01

Date Components

date
Components.java
Replay: real traced execution (multi-file project)
// Date components

import java.time.LocalDate;
import java.time.DayOfWeek;
import java.time.Month;

public class Components {

    public static void main(String[] args) {
        LocalDate date = LocalDate.of(2025, 1, 29);

        System.out.println("Date: " + date);
        System.out.println();

        // Year, month, day
        System.out.println("Year: " + date.getYear());
        System.out.println("Month (int): " + date.getMonthValue());
        System.out.println("Day: " + date.getDayOfMonth());

        // Month enum
        Month month = date.getMonth();
        System.out.println("\nMonth enum: " + month);
        System.out.println("Month name: " + month.name());
        System.out.println("Month value: " + month.getValue());

        // Day of week
        DayOfWeek dayOfWeek = date.getDayOfWeek();
        System.out.println("\nDay of week enum: " + dayOfWeek);
        System.out.println("Day name: " + dayOfWeek.name());
        System.out.println("Day value: " + dayOfWeek.getValue());  // 1=Monday, 7=Sunday

        // Day of year
        System.out.println("\nDay of year: " + date.getDayOfYear());

        // Era
        System.out.println("Era: " + date.getEra());  // CE or BCE

        // Check properties
        System.out.println("\nIs leap year: " + date.isLeapYear());
        System.out.println("Length of month: " + date.lengthOfMonth());
        System.out.println("Length of year: " + date.lengthOfYear());

        // Convert to epoch day
        long epochDay = date.toEpochDay();
        System.out.println("\nDays since epoch (1970-01-01): " + epochDay);

        // Multiple dates
        System.out.println("\nWeek dates:");
        LocalDate monday = LocalDate.of(2025, 1, 27);
        for (int i = 0; i < 7; i++) {
            LocalDate day = monday.plusDays(i);
            System.out.println(day + " is " + day.getDayOfWeek());
        }
    }

}

// Date components

import java.time.LocalDate;
import java.time.DayOfWeek;
import java.time.Month;

public class Components {

    public static void main(String[] args) {
        LocalDate date = LocalDate.of(2024, 2, 29);

        System.out.println("Date: " + date);
        System.out.println();

        // Year, month, day
        System.out.println("Year: " + date.getYear());
        System.out.println("Month (int): " + date.getMonthValue());
        System.out.println("Day: " + date.getDayOfMonth());

        // Month enum
        Month month = date.getMonth();
        System.out.println("\nMonth enum: " + month);
        System.out.println("Month name: " + month.name());
        System.out.println("Month value: " + month.getValue());

        // Day of week
        DayOfWeek dayOfWeek = date.getDayOfWeek();
        System.out.println("\nDay of week enum: " + dayOfWeek);
        System.out.println("Day name: " + dayOfWeek.name());
        System.out.println("Day value: " + dayOfWeek.getValue());  // 1=Monday, 7=Sunday

        // Day of year
        System.out.println("\nDay of year: " + date.getDayOfYear());

        // Era
        System.out.println("Era: " + date.getEra());  // CE or BCE

        // Check properties
        System.out.println("\nIs leap year: " + date.isLeapYear());
        System.out.println("Length of month: " + date.lengthOfMonth());
        System.out.println("Length of year: " + date.lengthOfYear());

        // Convert to epoch day
        long epochDay = date.toEpochDay();
        System.out.println("\nDays since epoch (1970-01-01): " + epochDay);

        // Multiple dates
        System.out.println("\nWeek dates:");
        LocalDate monday = LocalDate.of(2025, 1, 27);
        for (int i = 0; i < 7; i++) {
            LocalDate day = monday.plusDays(i);
            System.out.println(day + " is " + day.getDayOfWeek());
        }
    }

}

  1. date ← 2025-01-29, month ← JANUARY, dayOfWeek ← WEDNESDAY, epochDay ← 20117

    9public static void main(String[] args) {10    LocalDate date→ 2025-01-29 = LocalDate.of(2025, 1, 29); //@date=LocalDate.of(2025, 1, 29), LocalDate.of(2024, 2, 29)11    12    System.out.println("Date: " + date2025-01-29);13    System.out.println();1415    // Year, month, day16    System.out.println("Year: " + date.getYear());17    System.out.println("Month (int): " + date.getMonthValue());18    System.out.println("Day: " + date.getDayOfMonth());1920    // Month enum21    Month month→ JANUARY = date.getMonth();22    System.out.println("\nMonth enum: " + monthJANUARY);23    System.out.println("Month name: " + month.name());24    System.out.println("Month value: " + month.getValue());2526    // Day of week27    DayOfWeek dayOfWeek→ WEDNESDAY = date.getDayOfWeek();28    System.out.println("\nDay of week enum: " + dayOfWeekWEDNESDAY);29    System.out.println("Day name: " + dayOfWeek.name());30    System.out.println("Day value: " + dayOfWeek.getValue());  // 1=Monday, 7=Sunday3132    // Day of year33    System.out.println("\nDay of year: " + date.getDayOfYear());3435    // Era36    System.out.println("Era: " + date.getEra());  // CE or BCE3738    // Check properties39    System.out.println("\nIs leap year: " + date.isLeapYear());40    System.out.println("Length of month: " + date.lengthOfMonth());41    System.out.println("Length of year: " + date.lengthOfYear());4243    // Convert to epoch day44    long epochDay→ 20117 = date.toEpochDay();45    System.out.println("\nDays since epoch (1970-01-01): " + epochDay20117);4647    // Multiple dates48    System.out.println("\nWeek dates:");49    LocalDate monday→ 2025-01-27 = LocalDate.of(2025, 1, 27);50    for (int i = 0; i < 7; i++) {
    outputDate: 2025-01-29
Year: 2025
Month (int): 1
Day: 29

Month enum: JANUARY
Month name: JANUARY
Month value: 1

Day of week enum: WEDNESDAY
Day name: WEDNESDAY
Day value: 3

Day of year: 29
Era: CE

Is leap year: false
Length of month: 31
Length of year: 365

Days since epoch (1970-01-01): 20117

Week dates:

  2. day ← 2025-01-27

    pass 1 of 7
    49LocalDate monday = LocalDate.of(2025, 1, 27);50for (int i0 = 0; i < 7; i++) {51    LocalDate day→ 2025-01-27 = monday.plusDays(i0);52    System.out.println(day2025-01-27 + " is " + day.getDayOfWeek());53}
    output2025-01-27 is MONDAY
    All 7 passes — pass 1 is the card above
    passiday
    102025-01-27
    212025-01-28
    322025-01-29
    432025-01-30
    542025-01-31
    652025-02-01
    762025-02-02

  1. date ← 2024-02-29, month ← FEBRUARY, dayOfWeek ← THURSDAY, epochDay ← 19782

    9public static void main(String[] args) {10    LocalDate date→ 2024-02-29 = LocalDate.of(2024, 2, 29);11    12    System.out.println("Date: " + date2024-02-29);13    System.out.println();1415    // Year, month, day16    System.out.println("Year: " + date.getYear());17    System.out.println("Month (int): " + date.getMonthValue());18    System.out.println("Day: " + date.getDayOfMonth());1920    // Month enum21    Month month→ FEBRUARY = date.getMonth();22    System.out.println("\nMonth enum: " + monthFEBRUARY);23    System.out.println("Month name: " + month.name());24    System.out.println("Month value: " + month.getValue());2526    // Day of week27    DayOfWeek dayOfWeek→ THURSDAY = date.getDayOfWeek();28    System.out.println("\nDay of week enum: " + dayOfWeekTHURSDAY);29    System.out.println("Day name: " + dayOfWeek.name());30    System.out.println("Day value: " + dayOfWeek.getValue());  // 1=Monday, 7=Sunday3132    // Day of year33    System.out.println("\nDay of year: " + date.getDayOfYear());3435    // Era36    System.out.println("Era: " + date.getEra());  // CE or BCE3738    // Check properties39    System.out.println("\nIs leap year: " + date.isLeapYear());40    System.out.println("Length of month: " + date.lengthOfMonth());41    System.out.println("Length of year: " + date.lengthOfYear());4243    // Convert to epoch day44    long epochDay→ 19782 = date.toEpochDay();45    System.out.println("\nDays since epoch (1970-01-01): " + epochDay19782);4647    // Multiple dates48    System.out.println("\nWeek dates:");49    LocalDate monday→ 2025-01-27 = LocalDate.of(2025, 1, 27);50    for (int i = 0; i < 7; i++) {
    outputDate: 2024-02-29
Year: 2024
Month (int): 2
Day: 29

Month enum: FEBRUARY
Month name: FEBRUARY
Month value: 2

Day of week enum: THURSDAY
Day name: THURSDAY
Day value: 4

Day of year: 60
Era: CE

Is leap year: true
Length of month: 29
Length of year: 366

Days since epoch (1970-01-01): 19782

Week dates:

  2. day ← 2025-01-27

    pass 1 of 7
    49LocalDate monday = LocalDate.of(2025, 1, 27);50for (int i0 = 0; i < 7; i++) {51    LocalDate day→ 2025-01-27 = monday.plusDays(i0);52    System.out.println(day2025-01-27 + " is " + day.getDayOfWeek());53}
    output2025-01-27 is MONDAY
    All 7 passes — pass 1 is the card above
    passiday
    102025-01-27
    212025-01-28
    322025-01-29
    432025-01-30
    542025-01-31
    652025-02-01
    762025-02-02
date_components Individual parts of a date that can be extracted: year, month (1-12), day of month, day of week, day of year.

Comparing Dates

check
Compare.java
Replay: real traced execution (multi-file project)
// Compare dates

import java.time.LocalDate;

public class Compare {

    public static void main(String[] args) {
        LocalDate date1 = LocalDate.of(2025, 1, 29);
        LocalDate date2 = LocalDate.of(2025, 2, 15);
        LocalDate date3 = LocalDate.of(2025, 1, 29);

        System.out.println("Date 1: " + date1);
        System.out.println("Date 2: " + date2);
        System.out.println("Date 3: " + date3);
        System.out.println();

        // isBefore, isAfter
        System.out.println("date1.isBefore(date2): " + date1.isBefore(date2));
        System.out.println("date1.isAfter(date2): " + date1.isAfter(date2));

        // equals
        System.out.println("\ndate1.equals(date2): " + date1.equals(date2));
        System.out.println("date1.equals(date3): " + date1.equals(date3));

        // compareTo
        System.out.println("\ndate1.compareTo(date2): " + date1.compareTo(date2));  // negative
        System.out.println("date2.compareTo(date1): " + date2.compareTo(date1));  // positive
        System.out.println("date1.compareTo(date3): " + date1.compareTo(date3));  // zero

        // isEqual (handles null better)
        System.out.println("\ndate1.isEqual(date3): " + date1.isEqual(date3));

        // Today comparisons
        LocalDate today = LocalDate.of(2025, 1, 29);
        System.out.println("\nSample today: " + today);
        System.out.println("date1 is before today: " + date1.isBefore(today));
        System.out.println("date1 is after today: " + date1.isAfter(today));

        // Find earliest/latest
        LocalDate earliest = date1.isBefore(date2) ? date1 : date2;
        LocalDate latest = date1.isAfter(date2) ? date1 : date2;

        System.out.println("\nEarliest: " + earliest);
        System.out.println("Latest: " + latest);

        // Check if in range
        LocalDate check = LocalDate.of(2025, 1, 31);
        LocalDate start = LocalDate.of(2025, 1, 1);
        LocalDate end = LocalDate.of(2025, 2, 1);

        boolean inRange = !check.isBefore(start) && !check.isAfter(end);
        System.out.println("\n" + check + " is in range [" + start + ", " + end + "]: " + inRange);

        // Sort dates
        LocalDate[] dates = {
            LocalDate.of(2025, 3, 15),
            LocalDate.of(2025, 1, 10),
            LocalDate.of(2025, 2, 20)
        };

        System.out.println("\nBefore sort:");
        for (LocalDate d : dates) {
            System.out.println("  " + d);
        }

        java.util.Arrays.sort(dates);

        System.out.println("After sort:");
        for (LocalDate d : dates) {
            System.out.println("  " + d);
        }
    }

}

// Compare dates

import java.time.LocalDate;

public class Compare {

    public static void main(String[] args) {
        LocalDate date1 = LocalDate.of(2025, 1, 29);
        LocalDate date2 = LocalDate.of(2025, 2, 15);
        LocalDate date3 = LocalDate.of(2025, 1, 29);

        System.out.println("Date 1: " + date1);
        System.out.println("Date 2: " + date2);
        System.out.println("Date 3: " + date3);
        System.out.println();

        // isBefore, isAfter
        System.out.println("date1.isBefore(date2): " + date1.isBefore(date2));
        System.out.println("date1.isAfter(date2): " + date1.isAfter(date2));

        // equals
        System.out.println("\ndate1.equals(date2): " + date1.equals(date2));
        System.out.println("date1.equals(date3): " + date1.equals(date3));

        // compareTo
        System.out.println("\ndate1.compareTo(date2): " + date1.compareTo(date2));  // negative
        System.out.println("date2.compareTo(date1): " + date2.compareTo(date1));  // positive
        System.out.println("date1.compareTo(date3): " + date1.compareTo(date3));  // zero

        // isEqual (handles null better)
        System.out.println("\ndate1.isEqual(date3): " + date1.isEqual(date3));

        // Today comparisons
        LocalDate today = LocalDate.of(2025, 1, 29);
        System.out.println("\nSample today: " + today);
        System.out.println("date1 is before today: " + date1.isBefore(today));
        System.out.println("date1 is after today: " + date1.isAfter(today));

        // Find earliest/latest
        LocalDate earliest = date1.isBefore(date2) ? date1 : date2;
        LocalDate latest = date1.isAfter(date2) ? date1 : date2;

        System.out.println("\nEarliest: " + earliest);
        System.out.println("Latest: " + latest);

        // Check if in range
        LocalDate check = LocalDate.of(2025, 2, 15);
        LocalDate start = LocalDate.of(2025, 1, 1);
        LocalDate end = LocalDate.of(2025, 2, 1);

        boolean inRange = !check.isBefore(start) && !check.isAfter(end);
        System.out.println("\n" + check + " is in range [" + start + ", " + end + "]: " + inRange);

        // Sort dates
        LocalDate[] dates = {
            LocalDate.of(2025, 3, 15),
            LocalDate.of(2025, 1, 10),
            LocalDate.of(2025, 2, 20)
        };

        System.out.println("\nBefore sort:");
        for (LocalDate d : dates) {
            System.out.println("  " + d);
        }

        java.util.Arrays.sort(dates);

        System.out.println("After sort:");
        for (LocalDate d : dates) {
            System.out.println("  " + d);
        }
    }

}

  1. date1 ← 2025-01-29, date2 ← 2025-02-15, date3 ← 2025-01-29, today ← 2025-01-29

    7public static void main(String[] args) {8    LocalDate date1→ 2025-01-29 = LocalDate.of(2025, 1, 29);9    LocalDate date2→ 2025-02-15 = LocalDate.of(2025, 2, 15);10    LocalDate date3→ 2025-01-29 = LocalDate.of(2025, 1, 29);1112    System.out.println("Date 1: " + date12025-01-29);13    System.out.println("Date 2: " + date22025-02-15);14    System.out.println("Date 3: " + date32025-01-29);15    System.out.println();1617    // isBefore, isAfter18    System.out.println("date1.isBefore(date2): " + date1.isBefore(date22025-02-15));19    System.out.println("date1.isAfter(date2): " + date1.isAfter(date22025-02-15));2021    // equals22    System.out.println("\ndate1.equals(date2): " + date1.equals(date22025-02-15));23    System.out.println("date1.equals(date3): " + date1.equals(date32025-01-29));2425    // compareTo26    System.out.println("\ndate1.compareTo(date2): " + date1.compareTo(date22025-02-15));  // negative27    System.out.println("date2.compareTo(date1): " + date2.compareTo(date12025-01-29));  // positive28    System.out.println("date1.compareTo(date3): " + date1.compareTo(date32025-01-29));  // zero2930    // isEqual (handles null better)31    System.out.println("\ndate1.isEqual(date3): " + date1.isEqual(date32025-01-29));3233    // Today comparisons34    LocalDate today→ 2025-01-29 = LocalDate.of(2025, 1, 29);35    System.out.println("\nSample today: " + today2025-01-29);36    System.out.println("date1 is before today: " + date1.isBefore(today2025-01-29));37    System.out.println("date1 is after today: " + date1.isAfter(today2025-01-29));3839    // Find earliest/latest40    LocalDate earliest→ 2025-01-29 = date1.isBefore(date22025-02-15) ? date12025-01-29 : date2;41    LocalDate latest→ 2025-02-15 = date1.isAfter(date22025-02-15) ? date12025-01-29 : date2;42    43    System.out.println("\nEarliest: " + earliest2025-01-29);44    System.out.println("Latest: " + latest2025-02-15);4546    // Check if in range47    LocalDate check→ 2025-01-31 = LocalDate.of(2025, 1, 31); //@check=LocalDate.of(2025, 1, 31), LocalDate.of(2025, 2, 15)48    LocalDate start→ 2025-01-01 = LocalDate.of(2025, 1, 1);49    LocalDate end→ 2025-02-01 = LocalDate.of(2025, 2, 1);5051    boolean inRange→ true = !check.isBefore(start2025-01-01) && !check.isAfter(end2025-02-01);52    System.out.println("\n" + check2025-01-31 + " is in range [" + start2025-01-01 + ", " + end2025-02-01 + "]: " + inRangetrue);5354    // Sort dates55    LocalDate[] dates = {56        LocalDate.of(2025, 3, 15),57        LocalDate.of(2025, 1, 10),58        LocalDate.of(2025, 2, 20)59    };6061    System.out.println("\nBefore sort:");62    for (LocalDate d : dates) {
    outputDate 1: 2025-01-29
Date 2: 2025-02-15
Date 3: 2025-01-29
date1.isBefore(date2): true
date1.isAfter(date2): false

date1.equals(date2): false
date1.equals(date3): true

date1.compareTo(date2): -1
date2.compareTo(date1): 1
date1.compareTo(date3): 0

date1.isEqual(date3): true

Sample today: 2025-01-29
date1 is before today: false
date1 is after today: false

Earliest: 2025-01-29
Latest: 2025-02-15

2025-01-31 is in range [2025-01-01, 2025-02-01]: true

Before sort:

  2. for (LocalDate d : dates)

    pass 1 of 3
    61System.out.println("\nBefore sort:");62for (LocalDate d2025-03-15 : dates) {63    System.out.println("  " + d2025-03-15);64}
    output  2025-03-15
    All 3 passes — pass 1 is the card above
    passd
    12025-03-15
    22025-01-10
    32025-02-20

  3. java.util.Arrays.sort(dates);

    66java.util.Arrays.sort(dates);6768System.out.println("After sort:");69for (LocalDate d : dates) {
    outputAfter sort:

  4. for (LocalDate d : dates)

    pass 1 of 3
    68System.out.println("After sort:");69for (LocalDate d2025-01-10 : dates) {70    System.out.println("  " + d2025-01-10);71}
    output  2025-01-10
    All 3 passes — pass 1 is the card above
    passd
    12025-01-10
    22025-02-20
    32025-03-15

  1. date1 ← 2025-01-29, date2 ← 2025-02-15, date3 ← 2025-01-29, today ← 2025-01-29

    7public static void main(String[] args) {8    LocalDate date1→ 2025-01-29 = LocalDate.of(2025, 1, 29);9    LocalDate date2→ 2025-02-15 = LocalDate.of(2025, 2, 15);10    LocalDate date3→ 2025-01-29 = LocalDate.of(2025, 1, 29);1112    System.out.println("Date 1: " + date12025-01-29);13    System.out.println("Date 2: " + date22025-02-15);14    System.out.println("Date 3: " + date32025-01-29);15    System.out.println();1617    // isBefore, isAfter18    System.out.println("date1.isBefore(date2): " + date1.isBefore(date22025-02-15));19    System.out.println("date1.isAfter(date2): " + date1.isAfter(date22025-02-15));2021    // equals22    System.out.println("\ndate1.equals(date2): " + date1.equals(date22025-02-15));23    System.out.println("date1.equals(date3): " + date1.equals(date32025-01-29));2425    // compareTo26    System.out.println("\ndate1.compareTo(date2): " + date1.compareTo(date22025-02-15));  // negative27    System.out.println("date2.compareTo(date1): " + date2.compareTo(date12025-01-29));  // positive28    System.out.println("date1.compareTo(date3): " + date1.compareTo(date32025-01-29));  // zero2930    // isEqual (handles null better)31    System.out.println("\ndate1.isEqual(date3): " + date1.isEqual(date32025-01-29));3233    // Today comparisons34    LocalDate today→ 2025-01-29 = LocalDate.of(2025, 1, 29);35    System.out.println("\nSample today: " + today2025-01-29);36    System.out.println("date1 is before today: " + date1.isBefore(today2025-01-29));37    System.out.println("date1 is after today: " + date1.isAfter(today2025-01-29));3839    // Find earliest/latest40    LocalDate earliest→ 2025-01-29 = date1.isBefore(date22025-02-15) ? date12025-01-29 : date2;41    LocalDate latest→ 2025-02-15 = date1.isAfter(date22025-02-15) ? date12025-01-29 : date2;42    43    System.out.println("\nEarliest: " + earliest2025-01-29);44    System.out.println("Latest: " + latest2025-02-15);4546    // Check if in range47    LocalDate check→ 2025-02-15 = LocalDate.of(2025, 2, 15);48    LocalDate start→ 2025-01-01 = LocalDate.of(2025, 1, 1);49    LocalDate end→ 2025-02-01 = LocalDate.of(2025, 2, 1);5051    boolean inRange→ false = !check.isBefore(start2025-01-01) && !check.isAfter(end2025-02-01);52    System.out.println("\n" + check2025-02-15 + " is in range [" + start2025-01-01 + ", " + end2025-02-01 + "]: " + inRangefalse);5354    // Sort dates55    LocalDate[] dates = {56        LocalDate.of(2025, 3, 15),57        LocalDate.of(2025, 1, 10),58        LocalDate.of(2025, 2, 20)59    };6061    System.out.println("\nBefore sort:");62    for (LocalDate d : dates) {
    outputDate 1: 2025-01-29
Date 2: 2025-02-15
Date 3: 2025-01-29
date1.isBefore(date2): true
date1.isAfter(date2): false

date1.equals(date2): false
date1.equals(date3): true

date1.compareTo(date2): -1
date2.compareTo(date1): 1
date1.compareTo(date3): 0

date1.isEqual(date3): true

Sample today: 2025-01-29
date1 is before today: false
date1 is after today: false

Earliest: 2025-01-29
Latest: 2025-02-15

2025-02-15 is in range [2025-01-01, 2025-02-01]: false

Before sort:

  2. for (LocalDate d : dates)

    pass 1 of 3
    61System.out.println("\nBefore sort:");62for (LocalDate d2025-03-15 : dates) {63    System.out.println("  " + d2025-03-15);64}
    output  2025-03-15
    All 3 passes — pass 1 is the card above
    passd
    12025-03-15
    22025-01-10
    32025-02-20

  3. java.util.Arrays.sort(dates);

    66java.util.Arrays.sort(dates);6768System.out.println("After sort:");69for (LocalDate d : dates) {
    outputAfter sort:

  4. for (LocalDate d : dates)

    pass 1 of 3
    68System.out.println("After sort:");69for (LocalDate d2025-01-10 : dates) {70    System.out.println("  " + d2025-01-10);71}
    output  2025-01-10
    All 3 passes — pass 1 is the card above
    passd
    12025-01-10
    22025-02-20
    32025-03-15
immutability LocalDate cannot be modified after creation. Methods like plusDays() return a new LocalDate instance.

Parsing Dates

iso
Parse.java
Replay: real traced execution (multi-file project)
// Parse date string

import java.time.LocalDate;
import java.time.format.DateTimeFormatter;
import java.time.format.DateTimeParseException;
import java.util.Locale;

public class Parse {

    public static void main(String[] args) {
        // Parse ISO format (yyyy-MM-dd)
        String iso = "2025-01-29";
        LocalDate date1 = LocalDate.parse(iso);
        System.out.println("Parsed ISO: " + date1);

        // Parse with custom pattern
        String custom1 = "29/01/2025";
        DateTimeFormatter formatter1 = DateTimeFormatter.ofPattern("dd/MM/yyyy");
        LocalDate date2 = LocalDate.parse(custom1, formatter1);
        System.out.println("Parsed " + custom1 + ": " + date2);

        // Parse various formats
        String[] dateStrings = {
            "2025-12-25",
            "25/12/2025",
            "12-25-2025",
            "Dec 25, 2025"
        };

        DateTimeFormatter[] formatters = {
            DateTimeFormatter.ISO_LOCAL_DATE,
            DateTimeFormatter.ofPattern("dd/MM/yyyy"),
            DateTimeFormatter.ofPattern("MM-dd-yyyy"),
            DateTimeFormatter.ofPattern("MMM dd, yyyy", Locale.US)
        };

        System.out.println("\nParse various formats:");
        for (int i = 0; i < dateStrings.length; i++) {
            LocalDate date = LocalDate.parse(dateStrings[i], formatters[i]);
            System.out.println(dateStrings[i] + " -> " + date);
        }

        // Handle parse errors
        System.out.println("\nHandle parse errors:");
        String[] testDates = {
            "2025-01-29",
            "2025-13-01",   // invalid month
            "2025-02-30",   // invalid day
            "not-a-date"
        };

        for (String dateStr : testDates) {
            try {
                LocalDate date = LocalDate.parse(dateStr);
                System.out.println(dateStr + " -> " + date);
            } catch (DateTimeParseException e) {
                System.out.println(dateStr + " -> ERROR: " + e.getMessage());
            }
        }

        // Parse with validation
        System.out.println("\nSafe parse:");
        System.out.println(safeParseDate("2025-01-29"));
        System.out.println(safeParseDate("invalid"));

        // Parse from different separators
        String date3 = "2025/01/29";
        LocalDate parsed3 = LocalDate.parse(date3, DateTimeFormatter.ofPattern("yyyy/MM/dd"));
        System.out.println("\nParsed " + date3 + ": " + parsed3);

        // Parse with text month
        String date4 = "January 29, 2025";
        LocalDate parsed4 = LocalDate.parse(date4, DateTimeFormatter.ofPattern("MMMM dd, yyyy", Locale.US));
        System.out.println("Parsed " + date4 + ": " + parsed4);
    }

    public static LocalDate safeParseDate(String dateStr) {
        try {
            return LocalDate.parse(dateStr);
        } catch (DateTimeParseException e) {
            System.out.println("Invalid date: " + dateStr);
            return null;
        }
    }

}

// Parse date string

import java.time.LocalDate;
import java.time.format.DateTimeFormatter;
import java.time.format.DateTimeParseException;
import java.util.Locale;

public class Parse {

    public static void main(String[] args) {
        // Parse ISO format (yyyy-MM-dd)
        String iso = "2024-02-29";
        LocalDate date1 = LocalDate.parse(iso);
        System.out.println("Parsed ISO: " + date1);

        // Parse with custom pattern
        String custom1 = "29/01/2025";
        DateTimeFormatter formatter1 = DateTimeFormatter.ofPattern("dd/MM/yyyy");
        LocalDate date2 = LocalDate.parse(custom1, formatter1);
        System.out.println("Parsed " + custom1 + ": " + date2);

        // Parse various formats
        String[] dateStrings = {
            "2025-12-25",
            "25/12/2025",
            "12-25-2025",
            "Dec 25, 2025"
        };

        DateTimeFormatter[] formatters = {
            DateTimeFormatter.ISO_LOCAL_DATE,
            DateTimeFormatter.ofPattern("dd/MM/yyyy"),
            DateTimeFormatter.ofPattern("MM-dd-yyyy"),
            DateTimeFormatter.ofPattern("MMM dd, yyyy", Locale.US)
        };

        System.out.println("\nParse various formats:");
        for (int i = 0; i < dateStrings.length; i++) {
            LocalDate date = LocalDate.parse(dateStrings[i], formatters[i]);
            System.out.println(dateStrings[i] + " -> " + date);
        }

        // Handle parse errors
        System.out.println("\nHandle parse errors:");
        String[] testDates = {
            "2025-01-29",
            "2025-13-01",   // invalid month
            "2025-02-30",   // invalid day
            "not-a-date"
        };

        for (String dateStr : testDates) {
            try {
                LocalDate date = LocalDate.parse(dateStr);
                System.out.println(dateStr + " -> " + date);
            } catch (DateTimeParseException e) {
                System.out.println(dateStr + " -> ERROR: " + e.getMessage());
            }
        }

        // Parse with validation
        System.out.println("\nSafe parse:");
        System.out.println(safeParseDate("2025-01-29"));
        System.out.println(safeParseDate("invalid"));

        // Parse from different separators
        String date3 = "2025/01/29";
        LocalDate parsed3 = LocalDate.parse(date3, DateTimeFormatter.ofPattern("yyyy/MM/dd"));
        System.out.println("\nParsed " + date3 + ": " + parsed3);

        // Parse with text month
        String date4 = "January 29, 2025";
        LocalDate parsed4 = LocalDate.parse(date4, DateTimeFormatter.ofPattern("MMMM dd, yyyy", Locale.US));
        System.out.println("Parsed " + date4 + ": " + parsed4);
    }

    public static LocalDate safeParseDate(String dateStr) {
        try {
            return LocalDate.parse(dateStr);
        } catch (DateTimeParseException e) {
            System.out.println("Invalid date: " + dateStr);
            return null;
        }
    }

}

  1. iso ← 2025-01-29, date1 ← 2025-01-29, custom1 ← 29/01/2025, formatter1 ← Value(DayOfMonth,2)'/'Value(MonthOfYear,2)'/'Value(YearOfEra,4,19,EXCEEDS_PAD)

    10public static void main(String[] args) {11    // Parse ISO format (yyyy-MM-dd)12    String iso→ 2025-01-29 = "2025-01-29"; //@iso="2025-01-29", "2024-02-29"13    LocalDate date1→ 2025-01-29 = LocalDate.parse(iso2025-01-29);14    System.out.println("Parsed ISO: " + date12025-01-29);1516    // Parse with custom pattern17    String custom1→ 29/01/2025 = "29/01/2025";18    DateTimeFormatter formatter1→ Value(DayOfMonth,2)'/'Value(MonthOfYear,2)'/'Value(YearOfEra,4,19,EXCEEDS_PAD) = DateTimeFormatter.ofPattern("dd/MM/yyyy");19    LocalDate date2→ 2025-01-29 = LocalDate.parse(custom129/01/2025, formatter1Value(DayOfMonth,2)'/'Value(MonthOfYear,2)'/'Value(YearOfEra,4,19,EXCEEDS_PAD));20    System.out.println("Parsed " + custom129/01/2025 + ": " + date22025-01-29);2122    // Parse various formats23    String[] dateStrings = {24        "2025-12-25",25        "25/12/2025",26        "12-25-2025",27        "Dec 25, 2025"28    };2930    DateTimeFormatter[] formatters = {31        DateTimeFormatter.ISO_LOCAL_DATE,32        DateTimeFormatter.ofPattern("dd/MM/yyyy"),33        DateTimeFormatter.ofPattern("MM-dd-yyyy"),34        DateTimeFormatter.ofPattern("MMM dd, yyyy", Locale.US)35    };3637    System.out.println("\nParse various formats:");38    for (int i = 0; i < dateStrings.length; i++) {
    outputParsed ISO: 2025-01-29
Parsed 29/01/2025: 2025-01-29

Parse various formats:

  2. date ← 2025-12-25

    pass 1 of 4
    37System.out.println("\nParse various formats:");38for (int i0 = 0; i < dateStrings.length4; i++) {39    LocalDate date→ 2025-12-25 = LocalDate.parse(dateStrings[i]2025-12-25, formatters[i]Value(Year,4,10,EXCEEDS_PAD)'-'Value(MonthOfYear,2)'-'Value(DayOfMonth,2));40    System.out.println(dateStrings[i]2025-12-25 + " -> " + date2025-12-25);41}
    output2025-12-25 -> 2025-12-25
    All 4 passes — pass 1 is the card above
    passidateStrings[i]formatters[i]date
    102025-12-25Value(Year,4,10,EXCEEDS_PAD)'-'Value(MonthOfYear,2)'-'Value(DayOfMonth,2)2025-12-25
    2125/12/2025Value(DayOfMonth,2)'/'Value(MonthOfYear,2)'/'Value(YearOfEra,4,19,EXCEEDS_PAD)2025-12-25
    3212-25-2025Value(MonthOfYear,2)'-'Value(DayOfMonth,2)'-'Value(YearOfEra,4,19,EXCEEDS_PAD)2025-12-25
    43Dec 25, 2025Text(MonthOfYear,SHORT)' 'Value(DayOfMonth,2)','' 'Value(YearOfEra,4,19,EXCEEDS_PAD)2025-12-25

  3. String[] testDates =

    43// Handle parse errors44System.out.println("\nHandle parse errors:");45String[] testDates = {46    "2025-01-29",47    "2025-13-01",   // invalid month48    "2025-02-30",   // invalid day49    "not-a-date"50};
    output
Handle parse errors:

  4. for (String dateStr : testDates)

    pass 1 of 4
    52for (String dateStr2025-01-29 : testDates) {53    try {
    All 4 passes — pass 1 is the card above
    passdateStr
    12025-01-29
    22025-13-01
    32025-02-30
    4not-a-date

  5. date ← 2025-01-29

    pass 1 of 4
    52for (String dateStr : testDates) {53    try {54        LocalDate date→ 2025-01-29 = LocalDate.parse(dateStr2025-01-29);55        System.out.println(dateStr2025-01-29 + " -> " + date2025-01-29);56    } catch (DateTimeParseException e) {
    output2025-01-29 -> 2025-01-29
    All 4 passes — pass 1 is the card above
    passdateStrdate
    12025-01-292025-01-29
    22025-13-01—
    32025-02-30—
    4not-a-date—

  6. catch (DateTimeParseException e)

    pass 1 of 3
    55    System.out.println(dateStr + " -> " + date);56} catch (DateTimeParseException ejava.time.format.DateTimeParseException: Text '2025-13-01' could not be parsed: Invalid value for MonthOfYear (valid values 1 - 12): 13) {57    System.out.println(dateStr2025-13-01 + " -> ERROR: " + e.getMessage());58}
    output2025-13-01 -> ERROR: Text '2025-13-01' could not be parsed: Invalid value for MonthOfYear (valid values 1 - 12): 13
    All 3 passes — pass 1 is the card above
    passedateStr
    1java.time.format.DateTimeParseException: Text '2025-13-01' could not be parsed: Invalid value for MonthOfYear (valid values 1 - 12): 132025-13-01
    2java.time.format.DateTimeParseException: Text '2025-02-30' could not be parsed: Invalid date 'FEBRUARY 30'2025-02-30
    3java.time.format.DateTimeParseException: Text 'not-a-date' could not be parsed at index 0not-a-date

  7. System.out.println(" Safe parse:");

    61// Parse with validation62System.out.println("\nSafe parse:");63System.out.println(safeParseDate("2025-01-29"));64System.out.println(safeParseDate("invalid"));
    output
Safe parse:

  8. public static LocalDate safeParseDate(String dateStr)

    pass 1 of 2
    77public static LocalDate safeParseDate(String dateStr2025-01-29) {78    try {

  9. try

    pass 1 of 2
    77public static LocalDate safeParseDate(String dateStr) {78    try {79        return LocalDate.parse(dateStr2025-01-29);80    } catch (DateTimeParseException e) {

  10. System.out.println(safeParseDate("2025-01-29"));

    62System.out.println("\nSafe parse:");63System.out.println(safeParseDate("2025-01-29"));64System.out.println(safeParseDate("invalid"));
    output2025-01-29

  11. public static LocalDate safeParseDate(String dateStr)

    pass 2 of 2
    77public static LocalDate safeParseDate(String dateStrinvalid) {78    try {

  12. try

    pass 2 of 2
    77public static LocalDate safeParseDate(String dateStr) {78    try {79        return LocalDate.parse(dateStrinvalid);80    } catch (DateTimeParseException e) {

  13. catch (DateTimeParseException e)

    79    return LocalDate.parse(dateStr);80} catch (DateTimeParseException ejava.time.format.DateTimeParseException: Text 'invalid' could not be parsed at index 0) {81    System.out.println("Invalid date: " + dateStrinvalid);82    return null;83}
    outputInvalid date: invalid

  14. date3 ← 2025/01/29, parsed3 ← 2025-01-29, date4 ← January 29, 2025

    63    System.out.println(safeParseDate("2025-01-29"));64    System.out.println(safeParseDate("invalid"));6566    // Parse from different separators67    String date3→ 2025/01/29 = "2025/01/29";68    LocalDate parsed3→ 2025-01-29 = LocalDate.parse(date32025/01/29, DateTimeFormatter.ofPattern("yyyy/MM/dd"));69    System.out.println("\nParsed " + date32025/01/29 + ": " + parsed32025-01-29);7071    // Parse with text month72    String date4→ January 29, 2025 = "January 29, 2025";73    LocalDate parsed4→ 2025-01-29 = LocalDate.parse(date4January 29, 2025, DateTimeFormatter.ofPattern("MMMM dd, yyyy", Locale.US));74    System.out.println("Parsed " + date4January 29, 2025 + ": " + parsed42025-01-29);75}
    outputnull

Parsed 2025/01/29: 2025-01-29
Parsed January 29, 2025: 2025-01-29

  1. iso ← 2024-02-29, date1 ← 2024-02-29, custom1 ← 29/01/2025, formatter1 ← Value(DayOfMonth,2)'/'Value(MonthOfYear,2)'/'Value(YearOfEra,4,19,EXCEEDS_PAD)

    10public static void main(String[] args) {11    // Parse ISO format (yyyy-MM-dd)12    String iso→ 2024-02-29 = "2024-02-29";13    LocalDate date1→ 2024-02-29 = LocalDate.parse(iso2024-02-29);14    System.out.println("Parsed ISO: " + date12024-02-29);1516    // Parse with custom pattern17    String custom1→ 29/01/2025 = "29/01/2025";18    DateTimeFormatter formatter1→ Value(DayOfMonth,2)'/'Value(MonthOfYear,2)'/'Value(YearOfEra,4,19,EXCEEDS_PAD) = DateTimeFormatter.ofPattern("dd/MM/yyyy");19    LocalDate date2→ 2025-01-29 = LocalDate.parse(custom129/01/2025, formatter1Value(DayOfMonth,2)'/'Value(MonthOfYear,2)'/'Value(YearOfEra,4,19,EXCEEDS_PAD));20    System.out.println("Parsed " + custom129/01/2025 + ": " + date22025-01-29);2122    // Parse various formats23    String[] dateStrings = {24        "2025-12-25",25        "25/12/2025",26        "12-25-2025",27        "Dec 25, 2025"28    };2930    DateTimeFormatter[] formatters = {31        DateTimeFormatter.ISO_LOCAL_DATE,32        DateTimeFormatter.ofPattern("dd/MM/yyyy"),33        DateTimeFormatter.ofPattern("MM-dd-yyyy"),34        DateTimeFormatter.ofPattern("MMM dd, yyyy", Locale.US)35    };3637    System.out.println("\nParse various formats:");38    for (int i = 0; i < dateStrings.length; i++) {
    outputParsed ISO: 2024-02-29
Parsed 29/01/2025: 2025-01-29

Parse various formats:

  2. date ← 2025-12-25

    pass 1 of 4
    37System.out.println("\nParse various formats:");38for (int i0 = 0; i < dateStrings.length4; i++) {39    LocalDate date→ 2025-12-25 = LocalDate.parse(dateStrings[i]2025-12-25, formatters[i]Value(Year,4,10,EXCEEDS_PAD)'-'Value(MonthOfYear,2)'-'Value(DayOfMonth,2));40    System.out.println(dateStrings[i]2025-12-25 + " -> " + date2025-12-25);41}
    output2025-12-25 -> 2025-12-25
    All 4 passes — pass 1 is the card above
    passidateStrings[i]formatters[i]date
    102025-12-25Value(Year,4,10,EXCEEDS_PAD)'-'Value(MonthOfYear,2)'-'Value(DayOfMonth,2)2025-12-25
    2125/12/2025Value(DayOfMonth,2)'/'Value(MonthOfYear,2)'/'Value(YearOfEra,4,19,EXCEEDS_PAD)2025-12-25
    3212-25-2025Value(MonthOfYear,2)'-'Value(DayOfMonth,2)'-'Value(YearOfEra,4,19,EXCEEDS_PAD)2025-12-25
    43Dec 25, 2025Text(MonthOfYear,SHORT)' 'Value(DayOfMonth,2)','' 'Value(YearOfEra,4,19,EXCEEDS_PAD)2025-12-25

  3. String[] testDates =

    43// Handle parse errors44System.out.println("\nHandle parse errors:");45String[] testDates = {46    "2025-01-29",47    "2025-13-01",   // invalid month48    "2025-02-30",   // invalid day49    "not-a-date"50};
    output
Handle parse errors:

  4. for (String dateStr : testDates)

    pass 1 of 4
    52for (String dateStr2025-01-29 : testDates) {53    try {
    All 4 passes — pass 1 is the card above
    passdateStr
    12025-01-29
    22025-13-01
    32025-02-30
    4not-a-date

  5. date ← 2025-01-29

    pass 1 of 4
    52for (String dateStr : testDates) {53    try {54        LocalDate date→ 2025-01-29 = LocalDate.parse(dateStr2025-01-29);55        System.out.println(dateStr2025-01-29 + " -> " + date2025-01-29);56    } catch (DateTimeParseException e) {
    output2025-01-29 -> 2025-01-29
    All 4 passes — pass 1 is the card above
    passdateStrdate
    12025-01-292025-01-29
    22025-13-01—
    32025-02-30—
    4not-a-date—

  6. catch (DateTimeParseException e)

    pass 1 of 3
    55    System.out.println(dateStr + " -> " + date);56} catch (DateTimeParseException ejava.time.format.DateTimeParseException: Text '2025-13-01' could not be parsed: Invalid value for MonthOfYear (valid values 1 - 12): 13) {57    System.out.println(dateStr2025-13-01 + " -> ERROR: " + e.getMessage());58}
    output2025-13-01 -> ERROR: Text '2025-13-01' could not be parsed: Invalid value for MonthOfYear (valid values 1 - 12): 13
    All 3 passes — pass 1 is the card above
    passedateStr
    1java.time.format.DateTimeParseException: Text '2025-13-01' could not be parsed: Invalid value for MonthOfYear (valid values 1 - 12): 132025-13-01
    2java.time.format.DateTimeParseException: Text '2025-02-30' could not be parsed: Invalid date 'FEBRUARY 30'2025-02-30
    3java.time.format.DateTimeParseException: Text 'not-a-date' could not be parsed at index 0not-a-date

  7. System.out.println(" Safe parse:");

    61// Parse with validation62System.out.println("\nSafe parse:");63System.out.println(safeParseDate("2025-01-29"));64System.out.println(safeParseDate("invalid"));
    output
Safe parse:

  8. public static LocalDate safeParseDate(String dateStr)

    pass 1 of 2
    77public static LocalDate safeParseDate(String dateStr2025-01-29) {78    try {

  9. try

    pass 1 of 2
    77public static LocalDate safeParseDate(String dateStr) {78    try {79        return LocalDate.parse(dateStr2025-01-29);80    } catch (DateTimeParseException e) {

  10. System.out.println(safeParseDate("2025-01-29"));

    62System.out.println("\nSafe parse:");63System.out.println(safeParseDate("2025-01-29"));64System.out.println(safeParseDate("invalid"));
    output2025-01-29

  11. public static LocalDate safeParseDate(String dateStr)

    pass 2 of 2
    77public static LocalDate safeParseDate(String dateStrinvalid) {78    try {

  12. try

    pass 2 of 2
    77public static LocalDate safeParseDate(String dateStr) {78    try {79        return LocalDate.parse(dateStrinvalid);80    } catch (DateTimeParseException e) {

  13. catch (DateTimeParseException e)

    79    return LocalDate.parse(dateStr);80} catch (DateTimeParseException ejava.time.format.DateTimeParseException: Text 'invalid' could not be parsed at index 0) {81    System.out.println("Invalid date: " + dateStrinvalid);82    return null;83}
    outputInvalid date: invalid

  14. date3 ← 2025/01/29, parsed3 ← 2025-01-29, date4 ← January 29, 2025

    63    System.out.println(safeParseDate("2025-01-29"));64    System.out.println(safeParseDate("invalid"));6566    // Parse from different separators67    String date3→ 2025/01/29 = "2025/01/29";68    LocalDate parsed3→ 2025-01-29 = LocalDate.parse(date32025/01/29, DateTimeFormatter.ofPattern("yyyy/MM/dd"));69    System.out.println("\nParsed " + date32025/01/29 + ": " + parsed32025-01-29);7071    // Parse with text month72    String date4→ January 29, 2025 = "January 29, 2025";73    LocalDate parsed4→ 2025-01-29 = LocalDate.parse(date4January 29, 2025, DateTimeFormatter.ofPattern("MMMM dd, yyyy", Locale.US));74    System.out.println("Parsed " + date4January 29, 2025 + ": " + parsed42025-01-29);75}
    outputnull

Parsed 2025/01/29: 2025-01-29
Parsed January 29, 2025: 2025-01-29

Key Methods

  • now(): Current date
  • of(year, month, day): Create specific date
  • getYear(), getMonthValue(), getDayOfMonth(): Get components
  • plusDays(), minusDays(): Add/subtract days
  • isBefore(), isAfter(): Compare dates
  • parse(): From string

Common Operations

  • Add/subtract days, weeks, months, years
  • Compare dates
  • Get day of week
  • Calculate difference
  • Format to string

Exercise: Practical.java

Calculate how many days until the next birthday given a birth date