Add Hours to Time in Java 8

1. Introduction

Adding hours to a time is a common task in many applications, such as scheduling, alarms, or time zone adjustments. Java's java.time.LocalTime provides a straightforward API to handle time operations cleanly and effectively.

Key Points

1. LocalTime is part of Java's modern date and time API, which supports time without a date.

2. The plusHours method of LocalTime is used to add hours to a time, returning a new LocalTime instance.

3. Time calculations automatically roll over; for example, adding to the hour late in the day will adjust to the next day.

2. Program Steps

1. Import the LocalTime class.

2. Create a LocalTime instance.

3. Add hours to the LocalTime and print the result.

3. Code Program

import java.time.LocalTime;

public class TimeAddition {

    public static void main(String[] args) {
        // Step 2: Create a LocalTime instance
        LocalTime time = LocalTime.of(22, 15);  

        // Step 3: Add hours to the LocalTime
        LocalTime newTime = time.plusHours(4);

        // Print the original and the new time
        System.out.println("Original time: " + time);
        System.out.println("New time after adding 4 hours: " + newTime);
    }
}

Output:

Original time: 22:15
New time after adding 4 hours: 02:15

Explanation:

1. LocalTime.of(22, 15) creates a LocalTime instance representing 10:15 PM.

2. time.plusHours(4) adds 4 hours to the initial time. Since the addition goes beyond midnight, the time rolls over to 02:15 of the next day.

3. The LocalTime class handles time operations such that time is always maintained within a valid range (00:00 to 23:59), demonstrating how Java can automatically handle the overflow of time values, effectively managing time calculations without manual adjustments.