News
JetBrains and Spring Deepen Kotlin Integration for Backend Development
- By John K. Waters
- June 3, 2025
Software toolmaker JetBrains and the Spring Team at VMware have announced a strategic collaboration to enhance support for the Kotlin programming language in Spring-based backend development. The initiative aims to streamline Kotlin’s use in production-grade server-side applications, aligning ongoing work with rising industry adoption.
The collaboration will target key areas, such as improved null safety across the Spring ecosystem, official Spring documentation in Kotlin, and performance improvements through a new reflection library under development by JetBrains, kotlinx.reflect. The goal is to improve the experience for Kotlin developers using the Spring framework and to formalize what has so far been an informal alignment between the two engineering teams.
"We have heavily embraced Kotlin as a first-class language for Spring applications," said Juergen Hoeller, co-founder of the Spring Framework, in a joint statement with Spring committer Sébastien Deleuze. "Now we are making this a strategic collaboration."
Focus Areas of the Collaboration
- Full Null Safety: Improved type safety by default in Kotlin + Spring apps without extra configuration.
- Official Learning Materials: Kotlin-based tutorials and guides for developers learning Spring.
- Faster Reflection: JetBrains is building
kotlinx.reflect, optimized for use cases like dependency injection and serialization.
- DSL Enhancements: A new Bean Registration DSL is the first step in modernizing Spring configuration with Kotlin idioms.
Although some features are still in development, Kotlin is already widely adopted in the Spring community. Features such as named parameters, extension functions, and coroutine support have helped Kotlin become a popular choice for backend developers seeking concise, expressive code.
Rod Johnson, original creator of the Spring Framework, remarked during KotlinConf 2025, "Kotlin and Spring Boot is a wonderfully elegant and powerful stack." Kotlin’s syntax, he noted, reveals the full flexibility of modern Spring development.
Real-World Adoption and Developer Sentiment
According to internal Spring usage metrics, 27% of Spring developers now use Kotlin in some capacity. Companies like Expedia, Atlassian, and Mercedes-Benz.io are among the organizations actively using the language in Spring-based systems. The collaboration is expected to accelerate this trend by lowering the barriers to entry for Kotlin developers adopting Spring.
For more insights, Spring's Sébastien Deleuze discussed upcoming Kotlin-first features in his Spring Boot 4 presentation, while Rod Johnson shared historical context in his Kotlin and Spring retrospective during the same conference.
Related Resources
About the Author
John K. Waters is the editor in chief of a number of Converge360.com sites, with a focus on high-end development, AI and future tech. He's been writing about cutting-edge technologies and culture of Silicon Valley for more than two decades, and he's written more than a dozen books. He also co-scripted the documentary film Silicon Valley: A 100 Year Renaissance, which aired on PBS. He can be reached at [email protected].