Java String lastIndexOf() example

🎓 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 String lastIndexOf() method in Java programming and how to use it with an example.

1. String lastIndexOf() Method Overview

Definition:

The lastIndexOf() method in Java's String class returns the index of the last occurrence of the specified character or substring within the invoking string. If the character or substring doesn't exist, -1 is returned.

Syntax:

1. str.lastIndexOf(int ch)
2. str.lastIndexOf(int ch, int fromIndex)
3. str.lastIndexOf(String substring)
4. str.lastIndexOf(String substring, int fromIndex)

Parameters:

- ch: a character (Unicode code point).

- fromIndex: the index to start the search backward from.

- substring: a string to be searched.

Key Points:

- Returns the index of the last occurrence of the specified character or substring.

- Returns -1 if the character or substring is not found.

- The search begins at the specified fromIndex and moves backward, searching towards the beginning of this string.

- If the fromIndex argument is greater than or equal to the string's length, it starts the search at the end of the string.

2. String lastIndexOf() Method Example

public class LastIndexOfExample {
    public static void main(String[] args) {
        String sample = "JavaProgrammingJava";

        // Searching for a character's last occurrence
        int lastIndex1 = sample.lastIndexOf('a');
        System.out.println("Last occurrence of 'a': " + lastIndex1);

        // Searching backward from a specific index
        int lastIndex2 = sample.lastIndexOf('a', 10);
        System.out.println("Last occurrence of 'a' before index 10: " + lastIndex2);

        // Searching for a substring's last occurrence
        int lastIndex3 = sample.lastIndexOf("Java");
        System.out.println("Last occurrence of 'Java': " + lastIndex3);

        // Searching for a non-existent substring
        int lastIndex4 = sample.lastIndexOf("Hello");
        System.out.println("Searching for 'Hello': " + lastIndex4);
    }
}

Output:

Last occurrence of 'a': 17
Last occurrence of 'a' before index 10: 3
Last occurrence of 'Java': 15
Searching for 'Hello': -1

Explanation:

In the example:

1. We start by searching for the last occurrence of the character 'a' in the string "JavaProgrammingJava". It returns the index of the last occurrence.

2. Next, we search backward from index 10 to find the character 'a'. The method finds the last occurrence before that index.

3. Then, we search for the last occurrence of the substring "Java". The method provides the starting index of its last occurrence.

4. Lastly, we search for a non-existent substring "Hello". As it's not present in the string, -1 is returned.

Related Java String Class method examples

• Java String charAt() example
• Java String concat() example
• Java String contains() example
• Java String endsWith() example
• Java String equals() example
• Java String equalsIgnoreCase() example
• Java String getBytes() example
• Java String indexOf() example
• Java String isEmpty() example
• Java String lastIndexOf() example
• Java String length() example
• Java String replace() example
• Java String split() example
• Java String startsWith() example
• Java String substring() example
• Java String toLowerCase() example
• Java String toUpperCase() example
• Java String trim() example
• Java String valueOf() example

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