Claude
8cdfcd4d8d
the tracing agent, and a real reflection-collision trap Co-Authored-By: Claude Sonnet 5 <[email protected]> Claude-Session: https://claude.ai/code/session_01EQNA6DJ9VgCtW6zhCE8Xud
61 lines
3.0 KiB
Markdown
61 lines
3.0 KiB
Markdown
# GraalVM native images of a Spring Boot 4.1 application
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Companion project for [**GraalVM Native Images for Spring Boot 4.1: AOT Processing, the Tracing
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Agent, and a Real Reflection Failure**](https://ankurm.com/building-native-images-of-spring-boot-applications-with-graalvm-a-step-by-step-guide/)
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on ankurm.com.
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A small Spring Boot 4.1 web app, built and run three ways -- a plain `java -jar`, the same jar
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with Spring's AOT processing applied, and a GraalVM native image -- with every startup time,
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memory number, and failure message in this README and the linked post captured from a real run,
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not estimated.
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## Versions
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| Spring Boot | 4.1.1 |
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| JDK (JVM runs) | Temurin 25.0.4.1 |
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| GraalVM (native builds) | GraalVM Community Edition for JDK 25, build 25.0.2+10.1 |
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| `native-maven-plugin` | 1.1.8 (pinned by `spring-boot-starter-parent:4.1.1`'s dependency management; 1.1.14 is the latest on Maven Central as of this writing, but the parent's pinned version is what actually runs unless overridden) |
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The previous version of this project and its post assumed Spring Boot 3.x, JDK 17, and GraalVM
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22.3 -- two major generations behind. See [docs/01-versions-and-setup.md](docs/01-versions-and-setup.md)
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for how each version claim here was checked.
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## Quickstart
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```bash
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# 1. Plain JVM run (any JDK 25 build)
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mvn -DskipTests package
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java -jar target/app.jar
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# 2. Native image (needs a GraalVM distribution -- native-image ships bundled, no `gu install` step)
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export JAVA_HOME=/path/to/graalvm-25.0.2
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mvn -Pnative -DskipTests native:compile # NOT `mvn -Pnative package` -- see docs/02-building-the-image.md
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./target/graalvm-native-images
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```
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## What's in this chapter
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| Doc | Covers |
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| [01-versions-and-setup.md](docs/01-versions-and-setup.md) | Verified version claims; why `gu install native-image` is obsolete |
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| [02-building-the-image.md](docs/02-building-the-image.md) | AOT processing's real generated output; why `-Pnative package` alone does not build a native image |
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| [03-the-reflection-trap.md](docs/03-the-reflection-trap.md) | A real `ClassNotFoundException` from a runtime-computed `Class.forName`, the tracing-agent fix, and the metadata-collision trap that fix runs into |
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| [04-honest-limits.md](docs/04-honest-limits.md) | What native images cost you, and where Project Leyden fits as the non-full-native alternative |
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Every number quoted in the post is in [docs/output/](docs/output) as a trimmed, real transcript.
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## Measured, not estimated
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| | plain JVM | native image |
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| Startup ("Started ... in") | 3.472 s | 0.091 s (0.104 s with reflection hints added) |
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| RSS at idle | ~190.8 MB | ~105.5 MB |
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| Artifact size | 22 MB jar (+ a JDK install) | 93 MB self-contained executable |
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| Build time | ordinary `mvn package` | 4m 14s–4m 19s on 2 vCPU / 8 GB |
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Full transcripts: [docs/output/01-jvm-baseline.txt](docs/output/01-jvm-baseline.txt),
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[docs/output/02-native-build.txt](docs/output/02-native-build.txt),
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[docs/output/05-native-startup-fixed.txt](docs/output/05-native-startup-fixed.txt).
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