Spring has released Spring Boot 3 around a month ago. Because it is a major release, there are huge/breaking changes like required Java and Gradle versions upgraded. In this post I list these requirements and share my experience when migrating a few of my projects from Spring Boot 2 to Spring Boot 3.
Spring has created a migration guide which I refer to in this post a few times. Besides that I share my own experience when upgrading few of my own Spring projects. Let’s list the new requirements for Spring Boot 3;
javax.* library imports have changed with jakarta.*.Spring Boot 3 requires Java 17, so locally you need to install Java 17 and set it as a default in your IDE. I use Jetbrains IDEA, so need to change; Under IntelliJ => Preferences => Build, execution, deployment => Gradle, I had to set the Gradle JVM to: Project SDK (17). I use CircleCI as a continuous integration environment. I also need to update the base image which supports Java 11. Now I have a new image which supports Java 17.
I use gradle wrapper in my projects. So I increase the gradle version to 7.6 in below configuration;
wrapper{
gradleVersion = '7.6'
}
Then I run the gradle wrapper command which downloads Gradle 7.6 for my project.
To upgrade the project from Spring Boot 2 to Spring Boot 3 first I upgraded to the latest Spring Boot 2 version which is 2.7.7 when I upgraded my project.
After I see that it works with the latest Spring Boot 2 version then I upgraded to Spring Boot 3 with below updates;
plugins {
id 'org.springframework.boot' version '3.0.1'
}
After that I run gradle build to build and run the integration test in my project. My project
didn’t compile because of Jakarta EE changes. I list the some of the imports that I have changed;
- import javax.validation.Valid; -> import jakarta.validation.Valid;
- import javax.validation.constraints.NotNull; -> import jakarta.validation.constraints.NotNull;
- import javax.annotation.PostConstruct; -> import jakarta.annotation.PostConstruct;
- mport javax.annotation.PreDestroy; -> import jakarta.annotation.PreDestroy;
After fixing the compile time issues still application context couldn’t be up because of application.yml changes. Based on the migration document
With Spring Boot 3.0, a few configuration properties were renamed/removed and developers need to update their application.properties/application.yml accordingly. To help you with that, Spring Boot provides a spring-boot-properties-migrator module. Once added as a dependency to your project, this will not only analyze your application’s environment and print diagnostics at startup, but also temporarily migrate properties at runtime for you.
So I had added the migration library to build.gradle as follows;
runtimeOnly("org.springframework.boot:spring-boot-properties-migrator")
At that time I was writing that post there is a typo in that command in the original migration guide
Gradle doesn’t have a runtime as a dependency configuration, it should be runtimeOnly. After adding that library it shows the issues on the application logs.
In my case I need to replace spring.profiles.active to spring.config.activate.on-profile.
The last note is from Hibernate, however I don’t give much insight about it because I decided to remove my Spring Data JPA usage when I’m upgrading my projects.
In general I’m not a fan of Hibernate and it seems over complicated to configure the Id generator in the new version. I found that post which gives all the details
regarding the Hibernate 6 upgrade which needs to be done with Spring Boot 3.
Here is the PR I have done for all the changes explained in this post.
Spring released a major upgrade which makes the platform more stabilized with Jakarta EE changes.
Spring Boot 3 project announcement
Gradle Spring Boot Plugin Page
Sequence Naming Strategies In Hibernate 6
Happy coding :)