JCON 2023 Moritz Halbritter / Spring Boot @ VMware https://mhalbritter.github.io/ From Spring Native to Spring Boot 3 Copyright © 2020 VMware, Inc. or its affiliates. 

What’s a GraalVM native-image? Java Bytecode Native executable binary There’s a lot more stuff in it! 

Why compile to native? 

Why compile to native? Instant startup Milliseconds for native instead of seconds for the JVM No warmup Peak performance available immediately Low resource usage Lower memory footprint and no JIT compilation Reduced attack surface Closed world of dependencies with explicit reflection and serialization Compact packaging Smaller container easier to deploy 

Use cases for native images JVM likely better Assess Recommended Low memory and CPU Scale to zero Function as a Service Microservices Backoffices Container image distribution Very frequent deployment High traffic website Unsupported dependency Big monolithic application Huge memory and CPU Agent-based observability Kubernetes 

A little bit of history 2021-03-11 

It got official with Spring Boot 3 Spring Boot 3 introduces official support for compiling applications to native executables and supersedes Spring Native 

Demo: How to get started 

GraalVM 22.3 and 23.0 is supported ● GraalVM versions support policy: ● GraalVM 22.3 ● GraalVM 23.0 (... for JDK 17 / 20), released 2023-06-13 ○ Better performance ○ Compatibility improvements ○ Bundles ○ Experimental JMX support ○ Previous EE only features releases as “Oracle GraalVM” ■ G1, PGO, Compressed Object headers and pointers, … 

VMware Spring Runtime adds end-to-end native support ● VMware and Bellsoft now have a support agreement that provides end-to-end native support to VMware Spring Runtime customers ● Bellsoft Liberica NIK (based on the GraalVM Community Edition) and Liberica JDK are used in native Buildpacks ● Consistent with the JVM side where Liberica JDK is used ● Fixes and enhancements will be contributed upstream to GraalVM 

Library support based on GraalVM reachability metadata ● Native image configuration for JVM libraries ● Initially a GraalVM and Spring driven effort ● Guidelines on how to craft native configuration ○ Runtime initialization by default ○ No build-time initialization ○ Reachability based native configuration ○ Mandatory native testing 

Zero substitutions Fix the upstream libraries instead 

No explicit build time initialization Only runtime initialization 

RuntimeHints API No more fiddling with JSON 

Demo: Migrating PetClinic 

A peek under the covers 

Spring Boot 3 AOT and native support overview Native Build Tools GraalVM Spring Boot 3 AOT and native integration in Boot plugins AOT transformation engine Spring Framework 6 Paketo Buildpacks Native Buildpack AOT plugins Native documentation Spring portfolio (Data, Security, etc.) AOT transformations Native hints native-image compiler Reachability metadata repository 

Native compilation with Spring App compiled Compiled sources Resources AOT is done Compiled sources Resources AOT sources Native image config Compiled AOT sources Native binary Native application :generateAotSources + :aotClasses :nativeCompile Application Jar AOT optimized app :bootJar AOT classes 

Demo: A peek under the covers 

Conditions (e.g. Profiles) are possible 

Two way of building native executables Native Build Tools ● Started as a collaboration between Spring and GraalVM team, and recently the Micronaut team has joined ● Application compilation and testing support ● Requires local GraalVM native-image compiler ● Produces a native executable ○ Linux (x64, ARM) ○ MacOS (x64, ARM) ○ Windows (x64) 

Two way of building native executables Buildpacks ● Container based native builds based on Buildpacks ● Application compilation support ● Requires Docker but no local GraalVM installation ● Produces a Linux container image ○ x64 is supported ○ Official ARM support work in progress 

Data points 

Startup time (GraalVM 22.3) 

Scale to zero your Cloud deployments 

Performance (GraalVM 22.3) 

Simple webapp memory consumption (GraalVM 22.3) 

Petclinic container size (MiB, GraalVM 22.3) 

GraalVM 23.0 https://medium.com/graalvm/a-new-graalvm-release-and-new-free-license-4aab483692f5 

GraalVM 23.0 https://medium.com/graalvm/a-new-graalvm-release-and-new-free-license-4aab483692f5 

GraalVM 23.0 https://medium.com/graalvm/a-new-graalvm-release-and-new-free-license-4aab483692f5 

GraalVM 23.0 https://medium.com/graalvm/a-new-graalvm-release-and-new-free-license-4aab483692f5 

Observability 

Two ways of adding observability Using JVM agents ● Some agents work, when using the agent at build time ○ Fixed configuration! Using Micrometer Tracing ● First class support in (native) Spring 

Actuator is working in a native image > curlie :8080/actuator/prometheus process_cpu_usage 0.0 process_files_max_files 524288.0 executor_queued_tasks{name="applicationTaskExecutor",} 0.0 jvm_classes_unloaded_classes_total 0.0 tomcat_sessions_active_current_sessions 0.0 tomcat_sessions_created_sessions_total 0.0 executor_pool_core_threads{name="applicationTaskExecutor",} 8.0 process_uptime_seconds 43.158 system_load_average_1m 4.39404296875 jvm_threads_peak_threads 18.0 disk_free_bytes{path="/home/moe/Downloads/demo/.",} 1.24508004352E11 executor_pool_size_threads{name="applicationTaskExecutor",} 0.0 tomcat_sessions_rejected_sessions_total 0.0 tomcat_sessions_expired_sessions_total 0.0 executor_pool_max_threads{name="applicationTaskExecutor",} 2.147483647E9 

And tracing, too 

The Future Spring continues to follow and shape the GraalVM native image evolution 

Thank you! © 2020 Spring. A VMware-backed project. https://mhalbritter.github.io/