In this episode, I talk with Mark Thomas, the legendary and highly prolific committer to Apache Tomcat. Happy New Year!

Hi, Spring fans! Can you believe it? It's already the 30th of December! I celebrated Christmas with my family in Los Angeles, then we jumped on a flight headed for Southeast Asia to ring in the New Year with more friends and family. I'm sitting at a café in the sweltering city of Kuala Lumpur, Malaysia as I write this - looking back fondly at the last week of, and the entire year of, 2025.

That's right! It's time for my yearly tradition of retroactive year-end navel‑gazing and analysis; it's time for This Year in Spring, where we review the good, the great, and the amazing: the top five best…

Back in September 2016, nearly a decade ago now, we introduced Spring Vault as a integration layer for HashiCorp Vault within Spring applications, complemented by Spring Cloud Vault for Spring Boot arrangements. The core idea has always been straightforward: Externalizing secrets to encrypted Vault storage to reduce application-side complexity considerably, especially by leveraging Vault's secure primitives for communication and authentication.

VaultTemplate and its reactive counterpart ReactiveVaultTemplate have served us well, providing a familiar Java-based programming interface for…

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…

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! 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!

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…