[SpringIO2023] Going Native: Fast and Lightweight Spring Boot Applications with GraalVM
At Spring I/O 2023 in Barcelona, Alina Yurenko, a developer advocate at Oracle Labs, captivated the audience with her deep dive into GraalVM Native Image support for Spring Boot 3.0. Her session, a blend of technical insights, live demos, and community engagement, showcased how GraalVM transforms Spring Boot applications into fast-starting, lightweight native executables that eliminate the need for a JVM. By leveraging GraalVM’s ahead-of-time (AOT) compilation, developers can achieve significant performance gains, reduced memory usage, and enhanced security, making it a game-changer for cloud-native deployments.
GraalVM: Beyond a Traditional JDK
Alina began by demystifying GraalVM, a versatile platform that extends beyond a standard JDK. While it can run Java applications using the OpenJDK HotSpot VM with an optimized Graal compiler, the spotlight was on its Native Image feature. This AOT compilation process converts a Spring Boot application into a standalone native executable, stripping away runtime code loading and compilation. The result? Applications that start in fractions of a second and consume minimal memory. Alina emphasized that GraalVM’s ability to include only reachable code—application logic, dependencies, and necessary JDK classes—reduces binary size and enhances efficiency, a critical advantage for cloud environments where resources are costly.
Performance and Resource Efficiency in Action
Through live demos, Alina illustrated GraalVM’s impact using the Spring Pet Clinic application. On her laptop, the JVM version took 1.5 seconds to start, while the native executable launched in just 0.3 seconds—a fivefold improvement. The native version was also significantly smaller, at roughly 50 MB without compression, compared to the JVM’s bulkier footprint. To stress-test performance, Alina ran a million requests against a simple Spring Boot app, comparing JVM and native modes. The JVM achieved 80k requests per second, while the native image hit 67k. However, with profile-guided optimizations (PGO), which mimic JVM’s runtime profiling at build time, the optimized native version reached 81k requests per second, rivaling JVM peak throughput. These demos underscored GraalVM’s ability to balance startup speed, low memory usage, and competitive throughput.
Security and Compact Packaging
Alina highlighted GraalVM’s security benefits, noting that native images eliminate runtime code loading, reducing attack vectors like those targeting just-in-time compilation. Only reachable code is included, minimizing the risk of unused dependencies introducing vulnerabilities. Dynamic features like reflection require explicit configuration, ensuring deliberate control over runtime behavior. On packaging, Alina showcased how native images can be compressed using tools like UPX, achieving sizes as low as a few megabytes, though she cautioned about potential runtime decompression trade-offs. These features make GraalVM ideal for deploying compact, secure applications in constrained environments like Kubernetes or serverless platforms.
Practical Integration with Spring Boot
The session also covered GraalVM’s seamless integration with Spring Boot 3.0, which graduated Native Image support from the experimental Spring Native project to general availability in November 2022. Spring Boot’s AOT processing step optimizes applications for native compilation, reducing reflective calls and generating configuration files for GraalVM. Alina demonstrated how Maven and Gradle plugins, along with the GraalVM Reachability Metadata Repository, simplify builds by automatically handling library configurations. For developers, this means minimal changes to existing workflows, with tools like the tracing agent and Spring’s runtime hints easing the handling of dynamic features. Alina’s practical advice—develop on the JVM for fast feedback, then compile to native in CI/CD pipelines—resonated with attendees aiming to adopt GraalVM.