Java File length()

🎓 Top 15 Udemy Courses (80-90% Discount): My Udemy Courses - Ramesh Fadatare — All my Udemy courses are real-time and project oriented courses.

▶️ Subscribe to My YouTube Channel (178K+ subscribers): Java Guides on YouTube

▶️ For AI, ChatGPT, Web, Tech, and Generative AI, subscribe to another channel: Ramesh Fadatare on YouTube

In this guide, you will learn about the File length() method in Java programming and how to use it with an example.

1. File length() Method Overview

Definition:

The length() method of the File class returns the length of the file (in bytes) denoted by the File object. If the file does not exist, or if it's a directory, then this method returns 0.

Syntax:

public long length()

Parameters:

None.

Key Points:

- The method returns a long value representing the size of the file in bytes.

- If the file does not exist or if it's a directory, the method returns 0.

- It can be used to determine if a file is empty (i.e., its length is 0).

- This method doesn't throw exceptions if the file doesn't exist but simply returns 0.

- This method doesn't read the content of the file, so it's relatively efficient for checking the size of large files.

2. File length() Method Example

import java.io.File;

public class FileLengthExample {
    public static void main(String[] args) {
        // Creating a File object
        File file = new File("sample.txt");

        // Getting the length of the file
        long length = file.length();

        // Printing the length
        System.out.println("Length of sample.txt: " + length + " bytes");
    }
}

Output:

Length of sample.txt: 12345 bytes  // Assuming the file has 12345 bytes of data.

Explanation:

In the demonstrated example, a File object, file, representing the "sample.txt" file is created. When invoking the length() method on this object, it returns the size of the file in bytes. This is then printed out to the console. If "sample.txt" didn't exist or was a directory, the printed length would be 0 bytes. 

The length() method is beneficial to quickly gauge the size of a file without having to read its content.

My Top and Bestseller Udemy Courses. The sale is going on with a 70 - 80% discount. The discount coupon has been added to each course below:

Build REST APIs with Spring Boot 4, Spring Security 7, and JWT

🆕 High-Demand 80–90% OFF

[NEW] Learn Apache Maven with IntelliJ IDEA and Java 25

🆕 High-Demand 80–90% OFF

ChatGPT + Generative AI + Prompt Engineering for Beginners

🚀 Trending Now 80–90% OFF

Spring 7 and Spring Boot 4 for Beginners (Includes 8 Projects)

🔥 Bestseller 80–90% OFF
Available in Udemy for Business

Building Real-Time REST APIs with Spring Boot - Blog App

🔥 Bestseller 80–90% OFF
Available in Udemy for Business

Building Microservices with Spring Boot and Spring Cloud

🌟 Top Rated 80–90% OFF
Available in Udemy for Business

Java Full-Stack Developer Course with Spring Boot and React JS

🔥 Bestseller 80–90% OFF
Available in Udemy for Business

Build 5 Spring Boot Projects with Java: Line-by-Line Coding

🌟 Top Rated 80–90% OFF

Testing Spring Boot Application with JUnit and Mockito

🔥 Bestseller 80–90% OFF
Available in Udemy for Business

Spring Boot Thymeleaf Real-Time Web Application - Blog App

🔥 Bestseller 80–90% OFF
Available in Udemy for Business

Master Spring Data JPA with Hibernate

🔥 Bestseller 80–90% OFF
Available in Udemy for Business

Spring Boot + Apache Kafka Course - The Practical Guide

🎓 Student Favorite 80–90% OFF
Available in Udemy for Business

Java Testing: Mastering JUnit 5 Framework

🆕 New 80–90% OFF

Reactive Programming in Java: Spring WebFlux and Testing

🌟 Top Rated 80–90% OFF

Spring Boot + RabbitMQ Course - The Practical Guide

🌟 Top Rated 80–90% OFF
Available in Udemy for Business

Functional Programming in Java (Includes Java Collections)

🎓 Student Favorite 80–90% OFF

ChatGPT for Java Developers: Boost Your Productivity with AI

🚀 Trending Now 80–90% OFF