Spring Boot DevTools

3 min readJan 12, 2025

In this quick guide, we will explore Spring Boot DevTools, a set of tools designed to enhance the development experience when building Spring Boot applications. DevTools provides features such as automatic restart, live reload, and configurations that help speed up the development process.

Learn everything about Spring Boot: Spring Boot Tutorial.

What is Spring Boot DevTools?

Spring Boot DevTools is a module included in Spring Boot that helps developers by providing several convenient features aimed at improving the development experience. These features include automatic application restart, live reload of static resources, and additional development-time configurations.

Key Features of Spring Boot DevTools

1. Automatic Restart

DevTools automatically restarts your application whenever it detects changes in your classpath. This means you don’t have to manually restart your application every time you make a change, saving you a significant amount of time.

2. Live Reload

DevTools includes support for live reload of static resources, such as HTML, CSS, and JavaScript. When you make changes to these files, the browser will automatically refresh to show the latest changes.

3. Development-Time Configuration

DevTools provides additional development-time configurations that are useful during the development phase, such as:

Disabling template caching for quick feedback on template changes.
Enabling detailed error messages.

4. Remote Debugging

DevTools allows you to enable remote debugging and live reload features in a remote environment. This can be useful for testing changes on a server without needing a full redeployment.

Adding Spring Boot DevTools to Your Project

Using Maven

To add Spring Boot DevTools to your Maven project, include the following dependency in your pom.xml file:

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-devtools</artifactId>
    <scope>runtime</scope>
    <optional>true</optional>
</dependency>

Using Gradle

To add Spring Boot DevTools to your Gradle project, include the following dependency in your build.gradle file:

dependencies {
    developmentOnly 'org.springframework.boot:spring-boot-devtools'
}

Using Spring Boot DevTools

Automatic Restart

With DevTools included in your project, the automatic restart feature is enabled by default. Whenever you make changes to your code, Spring Boot will restart your application automatically.

Live Reload

To enable live reload, you need to install the LiveReload browser extension. Once installed, LiveReload will automatically refresh your browser when changes are detected in your static resources.

Install the LiveReload browser extension:

Go to the extension store for your browser (e.g., Chrome Web Store, Firefox Add-ons).
Search for and install the LiveReload extension.

Enable LiveReload:

Start your Spring Boot application.
Click the LiveReload icon in your browser to enable live reload for your application.

Development-Time Configuration

DevTools applies several development-time configurations automatically. These configurations are active only in the development environment and include:

Disabling Template Caching:

This is useful for web applications using templates like Thymeleaf, as changes to the templates will be reflected immediately without needing to restart the application.

Enabling Detailed Error Messages:

DevTools provides detailed error messages and stack traces, which are helpful during development.

Remote Debugging

To use DevTools’ remote debugging features, you need to enable remote support in your application.properties file:

spring.devtools.remote.secret=my-secret
spring.devtools.remote.context-path=/remote

On the remote server, start your application with the following command:

java -Dspring.devtools.remote.secret=my-secret -jar your-application.jar

Then, connect to the remote application using a tool like Spring Boot Remote, which is available in the Spring Tool Suite (STS) or IntelliJ IDEA.

Conclusion

In this guide, we have explored Spring Boot DevTools, a powerful module that enhances the development experience by providing features like automatic restart, live reload, and additional development-time configurations. By incorporating DevTools into your development workflow, you can save time and streamline the development process.