S5E24 - Jev, Java and Spring

Update: 2026-09-22

Description

Jev is a new model from TypeSafe that answers typed questions about your content. You send it some text and the decisions you need. It returns a probability, a choice, or a score instead of a paragraph. That makes it a natural fit for the decisions your code already has to make. Is this ticket urgent? Which team should own it? Which model should answer this prompt?

In this episode, Dan and DaShaun talk about why this matters for Java and Spring developers. Most of us have been asking a chat model to make a decision and then parsing prose to get the answer out. Jev gives you a typed answer you can branch on, with a confidence you can check. Dan shares what he learned getting it running in Java and Spring Boot, and the two of them talk through where a decision model fits next to Spring AI and where it does not.

Then it is your turn. Bring your questions about Jev, Spring Boot 4, Spring AI, or anything else in the Spring ecosystem. We will answer them live.

Show Notes:

Introducing System One Models & Jev - TypeSafe AI's launch post and the article Dan started with: a decision model, not an LLM
Spring AI and TypeSafe Jev: Fast, Cheap, Structured Decisions - Christian Tzolov's post from the morning of the show, with the spring-ai-starter-typesafe dependency, JevJudge, guardrail advisors, and seven runnable examples
spring-ai-typesafe on GitHub - the Spring AI Community project behind that starter: a Java SDK for the Jev API plus the Spring AI integrations
Getting Started with Jev in Java and Spring Boot - Dan's write-up of the single-file Java example and the Spring MVC RestClient version
jev-spring-boot-starter - the Spring Boot 4 starter Dan built over the weekend: RestClient, properties for the API key and model, records for the request and response
How Spring Boot 4 Starters Actually Work (I Built One for Jev) - Dan's video on building that starter
It's Not an LLM, So What Does It Do? 3 Real Apps I built with Jev - the examples Dan described on the show, including the model router and the real-time writing checks
spring-ai-model-router - the Spring AI example where Jev classifies the prompt and picks which model should answer it
Spring release calendar - DaShaun's favorite place to check what ships on September 24 and the milestones on the way to Spring Boot 4.2 in November
I Publish My Podcast with Claude Code and Skills - Dan's video on replacing this show's editing and publishing workflow with skills
Fundamentals of Software Engineering - Dan and Nate Schutta's book, with the career development chapter Dan pointed to
S5E23 - Java 27 Release Party with Billy Korando - last week's episode