Hi Spring fans, and happy holidays! I'm delighted to be joined again on this episode by my friend and fellow harbinger of doom (in the best possible way), Nate Schutta — co-author of the wonderful book Foundations of Software Engineering!

Happy holidays, everyone! The year may be winding down, but the Spring ecosystem continues unabated. We’re now a few weeks past the generational Spring Boot 4.0 release in November, and there have been tons of releases (and patches) since then. There’s also equal excitement reflected in posts from the community, so we’ve got a lot to dig into this week. So, without further ado…

• In last week’s installment of A Bootiful Podcast, I talked to the legendary Spring cofounder Juergen Hoeller
  https://spring.io/blog/2025/12/18/a-bootiful-podcast-juergen-hoeller
• Next-level Kotlin support in Spring Boot 4
  https://spring.io/blog/2025/12/18/next-level-kotlin-support-in-spring-boot-4
• Spring Shell 4.0.0-RC1 available now
  https://spring.io/blog/2025/12/19/spring-shell-4-0-0-rc1-released
• Spring Modulith 2.0.1, 1.4.6, and 1.3.12 released
  https://spring.io/blog/2025/12/20/spring-modulith-2-0-1-1-4-6-and-1-3-12-released
• Spring Tools 5 released
  …

When building AI agents with tool calling capabilities, developers often need insights into why an LLM chose a particular tool—not just which tool it selected. Understanding the model's reasoning process is important for debugging, observability, and building trustworthy AI systems.

Spring AI now (2.0.0-SNAPSHOT/1.1.3-SNAPSHOT) includes the Tool Argument Augmenter feature that enables dynamic augmentation of tool input schemas with additional arguments before sending tool definitions to the LLM. This allows AI applications to capture extra information from the model—such as reasoning, inner…

Hi, Spring fans! In this installment, we talk to the legendary cofounder of Spring itself, Juergen Hoeller, about the awesome new Spring Framework 7 release.

Happy holidays, one and all!

Following the announcement of the strategic partnership between JetBrains and Spring in May, I would like to share a global update on various Kotlin-related features and documentation enhancements we have made recently, with the goal of making Spring Boot 4 the best framework to develop backend applications with Kotlin.

Kotlin 2 baseline

Kotlin 2.0 introduced a new stable K2 compiler that compiles projects faster, performs smarter code analysis and allows the Kotlin team to evolve the language faster than with the K1 compiler. We recommend IntelliJ IDEA users to upgrade to 2025.3 to benefit…

Hi, Spring fans! Welcome to another installment of This Week in Spring! And what a week it’s been! We’ve got around nine shopping days ’til Christmas, and the New Year is almost here! Things are moving so quickly and the Spring community is no exception! Let's dive into this week's wonderful roundup!

• This is a super interesting application of a design pattern with Spring AI’s dynamic tool selection, described by Christian Tzolov.
• Spring Tools 5.0 released.
• Spring Shell 4.0.0-M2 is out!
• In last week’s installment of A Bootiful Podcast, I talked to Spring legend Rossen Stoyanchev about API versioning, declarative interface clients, RestTestClients, and more.
• Spring AI 2.0.0-M1 available now.
• Spring Framework 7.0.2 available now.
• Spring Framework 6.2.15 available now.
• Spring for GraphQL 1.3.7, 1.4.4, and 2.0.1 released.
• Spring Web Services 4.0.17 available now.
• Spring Security 2025-12 released…

Hi, Spring fans! Welcome to another installment of a Bootiful Podcast! In this installment I talk to the legendary Rossen Stoyanchev on API versioning, declarative interface clients, RestTestClients, and more!

As AI agents connect to more services—Slack, GitHub, Jira, MCP servers—tool libraries grow rapidly. A typical multi-server setup can easily have 50+ tools consuming 55,000+ tokens before any conversation starts. Worse, tool selection accuracy degrades when models face 30+ similarly-named tools.

The Tool Search Tool pattern, pioneered by Anthropic, addresses this: instead of loading all tool definitions upfront, the model discovers tools on-demand. It receives only a search tool initially, queries for capabilities when needed, and gets relevant tool definitions expanded into context. This achieves significant token savings while…

Hi, Spring fans! Welcome to another installment of This Week in Spring! I am in lovely New Jersey, the Garden State, as I write this and I spent most of the last week in New Orleans. It's been a busy week in the Spring community and beyond and so you know what that means? There's a ton of stuff to look into! Let's dive right into it!

• Spring gRPC 1.0.0 is now GA! Huzzah! Hooray!
• Want to learn more about the new release direct from the Spring team? Join them, live, for this webinar on the 11th.
• Good news, everybody, Spring Shell 4.0.0-M2 is available now!.
• Spring AI 1.1.1 is available now.
• I really enjoyed this discussion with fellow Spring Developer Advocate Dan Vega on his new book The Fundamentals of Software Engineering, and you can too.
• Did you see this amazing Kotlin DSL for HTMX, called KHTMX?
• Speaking of Kotlin, have you started your journey with this amazing language? Check out this guide on the Spring portal.
• While not strictly speaking related to Spring, I think this article on Idempotency Keys - a very useful design philosophy and pattern - by fellow Java Champion Gunnar Morling is well-worth a read if you care about building reliable distributed systems architectures…