Posts Tagged ‘JuergenHoeller’
[SpringIO2023] Spring Framework 6.1: Infrastructure Revisited by Juergen Hoeller
At Spring I/O 2023 in Barcelona, Juergen Hoeller, a pivotal figure in the Spring Framework, delivered an insightful session on the upcoming Spring Framework 6.1, focusing on its alignment with cutting-edge JVM innovations. Building on themes introduced in the conference keynote, Juergen explored how Spring Framework 6.1 integrates with OpenJDK’s Project Loom (virtual threads) and CRaC (Checkpoint/Restore), empowering developers to leverage these advancements for scalable, efficient applications. With Spring Framework 6.1 and Spring Boot 3.2 set for release in November 2023, this talk offered a forward-looking perspective on infrastructure enhancements already available in snapshots and slated for the first milestone in June 2023.
Modern Java and Jakarta EE Context
Juergen set the stage by outlining the Java and Jakarta EE landscape that Spring Framework 6.1 inhabits. Spring Framework 6.0 established a JDK 17 baseline, introducing language innovations like record types, sealed classes, and pattern matching, which provide a robust foundation for modern Java development. JDK 21, a long-term support release arriving in September 2023, builds on this with further enhancements, including sequence collections and virtual threads exiting preview. Spring Framework 6.1 aligns with JDK 21, enabling developers to adopt these features seamlessly. On the Jakarta EE front, Spring Framework 6.1 supports Jakarta EE 10, with plans to align with Jakarta EE 11’s anticipated JDK 21 requirement in 2024. This ensures compatibility with evolving servlet, JPA, and bean validation APIs, positioning Spring as a bridge to future Java ecosystems.
Virtual Threads: Scalability with Simplicity
A cornerstone of Juergen’s talk was Spring Framework 6.1’s integration with virtual threads, a transformative JVM feature in JDK 21. Virtual threads, lightweight and JVM-managed, allow blocking operations without tying up platform threads, enabling massive scalability with minimal resource overhead. Juergen explained that Spring’s task executor facilities, like SimpleAsyncTaskExecutor and a dedicated VirtualThreadTaskExecutor, are now virtual thread-ready. These allow developers to replace traditional thread pool configurations with virtual thread setups, requiring minimal code changes. In Spring MVC, virtual threads are configured at the servlet container level (e.g., Tomcat or Jetty), with upcoming Tomcat releases offering first-class support. For reactive stacks like Spring WebFlux, virtual threads serve as an escape hatch for integrating blocking operations, complementing the reactive model’s efficiency. Juergen emphasized that existing Spring MVC applications can achieve higher scalability or reduced memory footprints by adopting virtual threads, with no application code changes in ideal scenarios.
Checkpoint/Restore: Revolutionizing Startup Time
Juergen also delved into Spring Framework 6.1’s support for Project CRaC, which dramatically accelerates application startup through JVM snapshotting. By capturing a fully bootstrapped application state—potentially after warmup—and restoring it on demand, CRaC reduces startup times by a factor of at least 20 compared to traditional JVM bootstrapping. Spring Framework 6.1 integrates CRaC via its lifecycle model, using the 14-year-old Lifecycle interface to manage component stop and restart signals during checkpoint and restore phases. This ensures that embedded servers, message listeners, and other components pause cleanly and resume seamlessly. Juergen noted that most Spring applications are CRaC-compatible out of the box, though some components, like Tomcat adapters, require updates. Spring Boot 3.2 may introduce standard checkpoint options post-bootstrap, simplifying adoption. Currently supported by Azul’s OpenJDK and AWS Lambda SnapStart, CRaC promises significant benefits for dynamic scaling in Linux container deployments.
Practical Adoption and Future Outlook
Juergen underscored the practical readiness of these features, with Spring Framework 6.1 M1 slated for mid-June 2023 and Spring Boot 3.2 M1 for mid-July. Release candidates are planned for October, aligning with JDK 21’s September release, ensuring developers can adopt virtual threads and CRaC promptly. He encouraged experimentation, noting that benchmarking virtual threads or CRaC with existing applications is the best way to quantify benefits like scalability or reduced startup times. Looking ahead, Juergen highlighted a Spring.Next Buff session at Spring I/O for deeper discussions on these innovations. By aligning with JDK 21 and Jakarta EE 11, Spring Framework 6.1 positions developers to embrace the Java ecosystem’s future, delivering performance and efficiency without sacrificing Spring’s hallmark simplicity.