A Bootiful Podcast: Spring cofounder Juergen Hoeller on the amazing Spring Framework 7 release

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!...

Next level Kotlin support in Spring Boot 4

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...

This Week in Spring – December 16th, 2025

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...

A Bootiful Podcast: The legendary Rossen Stoyanchev on API versioning, declarative interface clients, RestTestClients, and more

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!...

Smart Tool Selection: Achieving 34-64% Token Savings with Spring AI's Dynamic Tool Discovery

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. T...

This Week in Spring - December 9th, 2025

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 ...

A Bootiful Podcast: Dan Vega on the fundamentals of software engineering

Hi, Spring fans! I'm so excited to chat with fellow Spring developer advocate Dan Vega about his new book, Fundamentals of Software Engineering...

Towards Spring Tools 5 - Ready for AI

There is no doubt that AI-based coding assistants are already or will be widely used by developers and within organizations. While the overall outlook is pretty certain, the exact way when and how to use those tools might vary, ranging from extensions for existing IDEs e.g. Copilot for Visual...

This Week in Spring - December 2nd, 2025

Hi, Spring fans! Welcome to another installment of This Week in Spring. By mistake, I inadvertently published older content in this installment, then tried to fix it and ended up re-publishing the same content. And, what's worse, I somehow ended up deleting the draft I had written for this...

Towards Spring Tools 5 - Stereotypes and a new Structural View

When working on Spring projects, developers do not only think in terms of low-level concepts like classes and interfaces. When using Spring, you think about higher-level abstractions and concepts like services, repositories, configuration classes, entities, aggregate roots, and so on. To bring...

A Bootiful Podcast: Spring community legend and friend Simon Martinelli

Hi, Spring fans! Happy Thanksgiving from me, and I am sure the entire Spring team, to you! We are, it should be clear, oh so very grateful.. thankful.. for you, the community. This week it is my great pleasure to chat with Spring community legend Simon Martinelli...

Beyond JSON: Converting Spring AI Tool Response Formats to TOON, XML, CSV, YAML, ...

JSON is the go-to format for LLM tool responses, but recent discussions around alternative formats like TOON Token-Oriented Object Notation claim potential benefits in token efficiency and performance. While the debate continues—with critical analyses pointing to context-dependent results—the...

Spring Data Ahead of Time Repositories - Part 2

Concluding the Road to GA blog post series, let's explore benefits of Spring Data AOT Repositories. Back in May 2025, we first introduced Ahead of Time AOT repositories as a preview feature for JPA and MongoDB with the 3rd Milestone of the next Spring Data generation. This feature, in short, uses...

This Week in Spring - Spring Boot 4 edition! - November 25th, 2025

Hi, Spring fans! Welcome to another illustrious installment of This Week in Spring! It’s Thanksgiving week here in the United States. Thanksgiving is traditionally celebrated with friends and family every fourth Thursday of November, gathered around a table full of food and, usually, a giant...

A Bootiful Podcast: The legendary Sébastien Deleuze on all that's new and nice in Spring Framework 7

Hi, Spring fans! Happy Spring Boot 4.0 release day! Make sure to get the bits on the Spring Initializr you know - start.spring.io! This release is packed with new features, a lot of which comes from Spring Framework 7. To help break it down for us this week, we’re joined by none other than the...

This Week in Spring - November 18th, 2025

This Week in Spring - November 18th, 2025 Hi, Spring fans! I'm thrilled to be in New York City for an exciting week of joint presentations on Spring AI + Bedrock and Spring Boot with the legendary James Ward. First up: we'll present a workshop at the AI Native Dev Conf today, then speak at the...

OpenTelemetry with Spring Boot

This is a new blog post in the Road to GA series, and this time we're taking a look at OpenTelemetry with Spring Boot. Introduction In modern cloud native architectures, observability is no longer optional; it is a fundamental requirement. You want to understand what your application is doing via...

A Bootiful Podcast: The legendary Bruce Eckel on language design, effects, abstraction, concurrency, and so much more

Hi, Spring fans! In this installment, I sit down with the legendary Bruce Eckel, who has probably forgotten more about programming languages than I will ever know, and whose book Thinking in Java helped launch me into a career...

Null-safe applications with Spring Boot 4

This is a new blog post in the Road to GA series, this time sharing an update on the status of the null-safety support across the Spring portfolio, as a follow-up of my previous related blog post Null Safety in Spring applications with JSpecify and NullAway and related Spring I/O talk. Are we...

Spring gRPC Next Steps for 1.0.0

This is a new blog post in the Road to GA series, this time updating everyone on the plans to integrate Spring gRPC with Spring Boot 4. The original plan was to move the autoconfiguration from Spring gRPC into Spring Boot in time for the 4.0 release. Unfortunately we haven't been able to find the...

LLM Response Evaluation with Spring AI: Building LLM-as-a-Judge Using Recursive Advisors

The challenge of evaluating Large Language Model LLM outputs is critical for notoriously non-deterministic AI applications, especially as they move into production. Traditional metrics like ROUGE and BLEU fall short when assessing the nuanced, contextual responses that modern LLMs produce. Human...

This Week in Spring - November 10th, 2025

Hi, Spring fans! Welcome to another installment of This Week in Spring! As I write this I am preparing for a flight to North Carolina first in flight!. This week's going to be busy, but next week even busier still! I'll be at AI By The Bay in San Francisco, AI Native Dev Con in NYC, and QCon SF i...

A Bootiful Podcast: The Vaadin team, live from Vaadin Create 2025

Hi, Spring fans! In this installment, I had the privilege to sit down with Vaadin legends Joonas Lehtinen, Marcus Hellberg, and Leif Åstrand at the amazing Vaadin Create 2025 event in Frankfurt, Germany...

Spring gRPC Next Steps for 1.0.0

This is a new blog post in the Road to GA series, this time updating everyone on the plans to integrate Spring gRPC with Spring Boot 4. The original plan was to move the autoconfiguration from Spring gRPC into Spring Boot in time for the 4.0 release. Unfortunately we haven't been able to find the...

This Week in Spring - November 4th, 2025

Hi, Spring fans! Welcome to another all-out installment of This Week in Spring wherein we attempt to recap all that's new and novel in the wild, wacky, and wonderful world of Springdom. And this week, I'm doing so from an airport in Switzerland, en route to Malmo, Sweden, for the amazing Oredev...

Create Self-Improving AI Agents Using Spring AI Recursive Advisors

The Spring AI ChatClient offers a fluent API for communicating with an AI model. The fluent API provides methods for building the constituent parts of a prompt that gets passed to the AI model as input. Advisors are a key part of the fluent API that intercept, modify, and enhance AI-driven...

A Bootiful Podcast: Elastic's developer advocate extraordinairre Philip Krenn on the state of logging

Hi, Spring fans! In this installment, we talk to my friend and Elastic's developer advocate extraordinairre Philip Krenn on the state of logging...

AWS Bedrock Prompt Caching Support in Spring AI

In our previous blog post about Anthropic prompt caching, we explored how prompt caching dramatically reduces API costs and latency by reusing previously processed prompt content. We introduced Spring AI's five strategic caching patterns for Anthropic Claude models and showed how they automatical...

Modularizing Spring Boot

Continuing our Road to GA series, this week we're exploring the modularization effort happening with Spring Boot 4. When Spring Boot 1.0 was released in 2014, it shipped with a single spring-boot-autoconfigure jar weighing in at 182 KiB. Of course, that initial version didn't support a great deal...

Introducing Spring AI Agents and Spring AI Bench

I'd like to introduce two new projects that are part of the Spring AI Community GitHub organization: Spring AI Agents, and Spring AI Bench. These two projects focus on using agentic coding tools—tools you likely already have in your enterprise. In 2025 AI coding agents have matured to the point...

This Week in Spring - October 28th, 2025

Hi, Spring fans! Welcome to another installment of This Week in Spring! It's a wonderful tuesday here in my home town of San Francisco as I write this from my condo's balcony, fresh off more than three weeks on the road. By the time we'll speak again in a week, Halloween will have come and gone...

Prompt Caching Support in Spring AI with Anthropic Claude

Large language model API costs can accumulate quickly when applications repeatedly send the same prompt content. A typical scenario: you're building a document analyzer that includes a 3,000-token document in every request. Five questions about that document means processing 15,000 tokens of...

A Bootiful Podcast: Spring team engineer Dariusz Jędrzejczyk on the latest-and-greatest in the reactive world, MCP, and more

Hi, Spring fans! In this installment we talk to the Spring team engineer Dariusz Jędrzejczyk on the latest-and-greatest in the reactive world, MCP, and more...

New Home for Spring Integration AWS

The Spring Integration for AWS was always an independent Spring Integration extension project with its own plans and release cycles. The consumption of this single jar library has always added a complexity from the dependency management perspective. It depends not only on Spring Integration modul...

This Week in Spring - October 21st, 2025

Hi, Spring fans! Welcome to another installment of This Week in Spring! I'm writing this from the fantastic Vaadin Create conference here in Frankfurt, Germany. What an amazing show and community. Since we last spoke, I have been in Boston; New York city; Sofia, Bulgaria; Krakow, Poland; and now...

Multi-Factor Authentication in Spring Security 7

In 2013, it was proposed to add multi-factor authentication into Spring Security. That was the year that “selfie” was added to the English dictionary and “What Does the Fox Say?” was a viral YouTube hit. Needless to say, one of the biggest features in Spring Security 7 is a long time coming, and ...

A Bootiful Podcast: Oracle VP and GraalVM founder Thomas Wuerthinger

Hi, Spring fans! In this installment I talk to Oracle VP and GraalVM founder Thomas Wuerthinger, recorded at Devoxx 2025!...

A Bootiful Podcast: Oracle VP and GraalVM founder Thomas Weurthinger

Hi, Spring fans! In this installment I talk to Oracle VP and GraalVM founder Thomas Weurthinger, recorded at Devoxx 2025!...

Introducing Share Consumer Support (Kafka Queues) in Spring for Apache Kafka

Continuing our Road to GA series, this week we're exploring Share Groups in Apache Kafka 4.0.0 and their integration in Spring for Apache Kafka 4.0.0 - a feature that fundamentally expands how we can consume messages from Kafka topics. When we first start working with Kafka, the mental model is...

This Week in Spring - October 14th, 2025

Hi, Spring fans! Welcome to another installment of This Week in Spring! I'm in Boston and New York city and Bulgaria and Poland this week, but I'm still hyped about last week's amazing Devoxx Belgium event! There are a ton of videos to look at, and I'll include just some of them here. So, without...

Spring Session MongoDB: Now Led by MongoDB Team

It gives me great pleasure to announce that the Spring Session MongoDB project will now be led by the MongoDB Team. NOTE: This announcement is in alignment with our announcement Spring Session Hazelcast: Now Led by Hazelcast Team. For ten years Spring Session has provided the infrastructure for...

Spring Session Hazelcast: Now Led by Hazelcast Team

It gives me great pleasure to announce that the Spring Session Hazelcast project will now be led by the Hazelcast Team. NOTE: This announcement is in alignment with our announcement Spring Session MongoDB: Now Led by MongoDB Team. For ten years Spring Session has provided the infrastructure for...

A Bootiful Podcast: Spring Security contributor Josh Cummings on the latest-and-greatest in Spring Security 7

Hi, Spring fans! In this installment we talk to Spring Security contributor and legend Josh Cummings...

This Week in Spring - October 7th, 2025

Hi, Spring fans! How're you doing this fantastic October afternoon? I'm on a train returning from Frankfurt, Germany, where I spoke at the Cloud Foundry Day Frankfurt event about how awesome it is to build an application with Spring Boot and Cloud Foundry. Yesterday I was in Antwerp, Belgium, and...

Introducing Jackson 3 support in Spring

This is a new blog post in the Road to GA series, this time sharing more details on the new Jackson 3 support, just a few days after Jackson 3.0.0 GA release, about to be introduced in Spring Boot 4 and related Spring portfolio projects. Jackson is by far the most used JSON library on the JVM, an...

A Bootiful Podcast: Dr. Kris De Volder on developer tooling for Spring developers and AI

Hi, Spring fans! In this installment we talk to Spring tooling legend Dr. Kris De Volder on tooling, AI, and so much more...

The state of HTTP clients in Spring

This is a new blog post in the Road to GA series, this time exploring the new capabilities of our HTTP clients. This is also a good time to reflect on the state of HTTP clients in Spring, so we will use this opportunity to explain an important announcement: we are officially deprecating...

Securing MCP Servers with Spring AI

Model Context Protocol, or MCP for short, has taken over the AI world. If you've been following our blog, you've probably read the introduction to the topic, Connect Your AI to Everything: Spring AI's MCP Boot Starters. The security aspects of MCP have been evolving fast, and the latest version o...

This Week in Spring: September 30th, 2025

Hi, Spring fans! As I write this I am about to board a flight for Colorado for the amazing Dev2Next conference! I'll be in Antwerp, Beglium for the amazing Devoxx event next week, and I'll be speaking at the Amsterdam JUG with James Ward on the Thursday after that, too! If you're around, be sure ...

A Bootiful Podcast: Spring Batch lead Mahmoud Ben Hassine

Hi, Spring fans! In this installment we talk to the legendary lead of the Spring Batch project, Mahmoud Ben Hassine, about the latest-and-greatest in Spring Batch in the Spring Boot 4 generation...