Getting started with Spring Boot 3.0

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Introduction

Spring Boot is a popular framework for building web applications and microservices in Java. The latest version, Spring Boot 3, released in September 2021. And it brings a number of new features and improvements to the framework.

One of the main new features in Spring Boot 3 is support for Java 16. This means that developers can now take advantage of the latest features. It’s improvements in the Java language when building their applications.

Another notable improvement in Spring Boot 3 is the introduction of a new feature that is “AppStartup”. This feature allows developers to register callbacks that run at different stages of the application startup process. This can be useful for performing tasks such as initializing resources. Also checking for configuration errors before the application starts accepting requests.

In addition to these new features, Spring Boot 3 also includes a number of bug fixes and performance improvements. For example, the framework now uses a new algorithm for resolving dependencies. This results in faster startup times and lower memory usage.

Although the great feature of Spring Boot 3 is:

It is fully compatible with Spring 5, which means that developers can take advantage of the latest features. Another is improvements in the Spring Framework without having to make any major changes to their code.

This Major Version of Spring Boot 3.0 and How to Prepare for the Transformations?

Java 16 Support: The latest version of the Java language, Java 16, is now supported by Spring Boot 3.0. This means that you can use Java 16 features in your applications if you choose to upgrade to this version of Spring Boot.
Gradle 7 Support: Spring Boot 3.0 now supports Gradle 7, the latest version of the popular build tool. If you are using Gradle with Spring Boot, you may need to update your build configuration to work with the new version of Gradle.
Reactive Web Client: The new reactive web client in Spring Boot 3.0 allows you to perform HTTP requests in a reactive manner. This is a major change from the traditional blocking web client in previous versions of Spring Boot. You will need to update your code to use the new reactive web client if you want to take advantage of this feature.
Micrometer Metrics: Micrometer, is a popular monitoring and metrics library. It’s now included as the default metrics library in Spring Boot 3.0. If you were previously using another metrics library with Spring Boot, you will need to update your code to use Micrometer.
OAuth 2.0 Improvements: Spring Boot 3.0 includes improvements to the OAuth 2.0 support. It’s making it easier to secure your applications using this popular authentication and authorization protocol.

How to Proceed

To prepare for these changes, you should familiarize yourself with the new features and improvements in Spring Boot 3.0. Also, the plan is to update your applications accordingly. It is also a good idea to test your applications with the new version of Spring Boot. Before deploying to production, ensure that everything works as expected. Additionally, you may want to consider updating any dependencies or libraries used by your application. As these may also need to update to be compatible with Spring Boot 3.0.

Spring Boot 3 Dependency Upgrades

In Spring Boot 3.0, several dependencies have been upgraded to their latest versions. Some of the notable upgrades include:

Spring Framework: The underlying Spring Framework has been upgraded to version 5.4, which brings new features and improvements to the framework.
Gradle: Spring Boot 3.0 now supports Gradle 7, the latest version of the popular build tool.
Micrometer: Micrometer, a popular monitoring and metrics library, is now included as the default metrics library in Spring Boot 3.0.
Reactor: The reactive programming library Reactor has been upgraded to version 3.4, which brings new features and improvements to the reactive programming support in Spring Boot.
Jackson: The JSON processing library Jackson has been upgraded to version 2.12, which brings new features and improvements to the JSON serialization and deserialization capabilities in Spring Boot.

These are just a few of the notable dependency upgrades in Spring Boot 3.0. If you are using any of these dependencies in your application, you may need to update your code. That could be compatible with the latest versions. It’s still a good idea to reevaluate the release notes. Upgrade guides for each dependency to understand the changes and any potential impact on your application.

New Features In Spring Boot 3

Spring Boot 3.0 is the latest version of the popular framework for building web applications and microservices in Java. It was released in September 2021 and includes several new features and improvements. Some of the notable new features in Spring Boot 3.0 are:

Support for Java 16: Spring Boot 3.0 now supports the latest version of Java, which means developers can take advantage of the latest features and improvements in the Java language when building their applications.
AppStartup: Spring Boot 3.0 introduces a new feature called “AppStartup” that allows developers to register callbacks that are executed at different stages of the application startup process. This can be useful for performing tasks such as initializing resources or checking for configuration errors before the application starts accepting requests.
Faster startup times and lower memory usage: Spring Boot 3.0 uses a new algorithm for resolving dependencies which result in faster startup times and lower memory usage.
Compatible with Spring 5: Spring Boot 3.0 is fully compatible with Spring 5, which means developers can take advantage of the latest features and improvements in the Spring Framework without having to make any major changes to their code.
New Actuator endpoints: Spring Boot 3.0 adds new Actuator endpoints that allow you to monitor and manage your application more easily.
Improved Error Handling: Spring Boot 3.0 has improved error handling capabilities, which makes it easier to handle exceptions and provides more useful error messages to clients.
Improved Security: Spring Boot 3.0 includes several security improvements, such as better handling of cookies, improved support for OAuth2, and support for JSON Web Tokens (JWT)
Support for Kotlin: Spring Boot 3.0 now supports the Kotlin programming language which is a modern, statically typed language that runs on the JVM.

How to Proceed

The main new features in Spring Boot 3.0 that can use in Java are related to the new AppStartup feature and the support for Java 16. Here are some examples of how these new features can used in your Java code:

AppStartup: To use the AppStartup feature, you can create an implementation of the AppStartup interface and register it as a Spring bean. For example:

Support for Java 16: To take advantage of the new features in Java 16, you can simply update the Java version in your build file and start using the new features in your code. For example, you can use the new “text blocks” feature to make it easier to write multi-line strings:

Additionally, Spring Boot 3.0 also includes several new features. Like- improvements related to the Actuator endpoints, improved error handling, and improved security. For example, you can use the new Actuator endpoints to monitor and manage your application more easily.

You can also use the improved error handling to handle exceptions and provide more useful error messages to clients.
for example:

These are just a few examples of how you can use the new features. And improvements in Spring Boot 3.0 in your Java code.

Summary

Overall, Spring Boot 3 is a solid release that brings a number of new features and improvements to the framework. It is a great choice for building web applications and microservices in Java. Developers should consider upgrading to this version if they are currently using an older version of Spring Boot.