Spring Boot 4 migration recipe

[Laurens-W]

What problem are you trying to solve?

Prepare for the Spring Boot 4 release later this year

Describe the solution you'd like

A Yaml recipe that can be used to compose the migration recipes
Early draft PRs with test cases so the community can provide feedback

Additional context

https://github.com/spring-projects/spring-boot/wiki/Spring-Boot-4.0-Release-Notes
The official release will probably be somewhere towards November see source, final paragraph

Are you interested in contributing this feature to OpenRewrite?

[sruffatti]

Here is a start! Please review: #766

[wyfrel]

@sruffatti : I've noticed that the LocalServerPort annotation is moved from org.springframework.boot.test.web.server.LocalServerPort to org.springframework.boot.web.server.test.LocalServerPort.

org.springframework.lang.Nullable is deprecated in favor of org.jspecify.annotations.Nullable

I don't want to mess up with your MR may be you can add a recipe for theses ?

[sruffatti]

@timtebeek without merging my MR to main, how do you suggest I go about getting others from the community to contribute to the Spring Boot 4.0 migration?

[Laurens-W]

Hey @sruffatti, in Tim's absence I'll suggest the following:

Recipes for the SpringBoot 4 migration can be developed separately and have a comment added to them like

// This needs to be added to the org.openrewrite.java.spring.boot3.UpgradeSpringBoot_4_0 recipe

That way we can easily compose the UpgradeSpringBoot_4_0 recipe in a few weeks when we get closer to it being released!

[timtebeek]

There's a nice blog series that goes into more depth on various aspects of the Spring Boot 4 release & changes:
https://spring.io/blog/2025/09/02/road_to_ga_introduction

Some of these may translate into good isolated items for recipes.

• Core Spring Resilience Features: @ConcurrencyLimit, @retryable, and RetryTemplate
• API Versioning in Spring
• HTTP Service Client Enhancements
• The state of HTTP clients in Spring
• Introducing Jackson 3 support in Spring
• Share Consumer - aka Kafka Queues in Spring Kafka
• Modularizing Spring Boot
• Progressive Authorization in Spring Security
• Spring gRPC - a New Spring Boot Module
• Null-Safe applications with Spring Boot 4
• OpenTelemetry with Spring Boot
• Ahead of Time Repositories (Part 2)