Hi Spring fans! Welcome to another installment of This Week in Spring! It's April 7th, 2026, and I'm on the road! I started the journey for the amazing Voxxed Days Amsterdam show and am now winding my way through France. I visited Colmar, a beautiful city from which the animators on Disney's Beauty and the Beast drew some inspiration. Now I'm off to Lyon, to see some of my French colleagues and explore one of the centers of gastronomy in the world. Then, it's off to Paris, where I'll be speaking at the Java User Group this Thursday! If you're local, don't miss it (ne le ratez pas!)

In the meantime, we've got a ton of stuff to go over so let's dive right into it.

How We Built an Java AI Agent by Connecting the Dots in the Ecosystem

  • This is an awesome look at how Trivago uses Spring Boot and GraalVM at scale.
  • I have been loving Craig Walls' Spring AI Recipes! His latest looks at using Spring AI's ChatClient for a lightweight chat loop.
  • Did you see the JetBrains team's blog on using Spring Data JPA more elegantly with Kotlin? JPA has its place, but the requirement that it controls the stateful mutations of the entities makes it very verbose when used with either Java or Kotlin. Especially when compared to every other ORM I can think of, including MyBatis, JOOQ, Spring Data JDBC, JDBI, JetBrains' Exposed, etc. So I was very happy to see this blog post!
  • This is a very interesting comparison between LangChain4j and Spring AI (and I love how well Spring AI did)
  • Eeeenteresting post: fake it till you make it: fault injection with Spring using headers and baggage propagation
  • I really enjoyed this amazing look at the extent to which Apero CAS has gone to efficiently test their Spring-based open-source project - 12000+ tests! - using Spring!