Comment maîtriser GraalVM pour des apps natives en 2026

#!/bin/bash

# Télécharger GraalVM CE 22.3.0 (adaptez la version)
wget https://github.com/graalvm/graalvm-ce-builds/releases/download/jdk-22.0.1/graalvm-community-jdk-22.0.1_linux-x64_bin.tar.gz

tar -xzf graalvm-community-jdk-22.0.1_linux-x64_bin.tar.gz

export JAVA_HOME=$PWD/graalvm-community-openjdk-22.0.1+8.1

export PATH=$JAVA_HOME/bin:$PATH

gu install native-image

gu install js  # Optionnel: pour polyglot JS

echo "GraalVM installé. Vérifiez: native-image --version"

public class HelloGraal {
    public static void main(String[] args) {
        System.out.println("Hello from GraalVM Native Image!");
        for (int i = 0; i < 5; i++) {
            System.out.println("Iteration " + i + ": Performance native!");
        }
    }
}

#!/bin/bash

javac -cp . HelloGraal.java

# Build native image (optimisé)
native-image \
  --no-fallback \
  --enable-https \
  --enable-http \
  --allow-incomplete-classpath \
  -O \
  -march=native \
  -o hellograal HelloGraal

# Test
./hellograal

time ./hellograal  # Mesure perf
du -h hellograal   # Taille ~10-20 Mo

import java.lang.reflect.Method;

public class ReflectiveApp {
    public static void main(String[] args) throws Exception {
        Class<?> clazz = Class.forName("java.lang.String");
        Method method = clazz.getMethod("toUpperCase");
        String result = (String) method.invoke("hello graal");
        System.out.println("Reflected: " + result);
    }

    public static void dynamicMethod() {
        System.out.println("Méthode dynamique appelée!");
    }
}

[
  {
    "name": "java.lang.String",
    "allDeclaredConstructors": true,
    "allPublicMethods": true,
    "allDeclaredMethods": true,
    "allDeclaredFields": true
  },
  {
    "name": "ReflectiveApp",
    "methods": [
      {"name": "dynamicMethod", "parameterTypes": []}
    ]
  }
]

#!/bin/bash

javac ReflectiveApp.java

native-image \
  --no-fallback \
  -H:+ReportExceptionStackTraces \
  -H:ReflectionConfigurationFiles=reflect-config.json \
  -H:ResourceConfigurationFiles=resource-config.json \
  -O \
  -o reflective-app ReflectiveApp

./reflective-app

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.example</groupId>
  <artifactId>graal-spring</artifactId>
  <version>1.0</version>
  <properties>
    <java.version>17</java.version>
    <spring-boot.version>3.2.0</spring-boot.version>
    <graalvm.version>22.3.0</graalvm.version>
  </properties>
  <dependencies>
    <dependency>
      <groupId>org.springframework.boot</groupId>
      <artifactId>spring-boot-starter-web</artifactId>
    </dependency>
    <dependency>
      <groupId>com.h2database</groupId>
      <artifactId>h2</artifactId>
      <scope>runtime</scope>
    </dependency>
  </dependencies>
  <build>
    <plugins>
      <plugin>
        <groupId>org.graalvm.buildtools</groupId>
        <artifactId>native-maven-plugin</artifactId>
        <version>0.10.2</version>
        <extensions>true</extensions>
        <executions>
          <execution>
            <goals><goal>native-compile</goal></goals>
          </execution>
        </executions>
      </plugin>
    </plugins>
  </build>
</project>

package com.example;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;

@SpringBootApplication
public class GraalSpringApplication {
    public static void main(String[] args) {
        SpringApplication.run(GraalSpringApplication.class, args);
    }
}

@RestController
class HelloController {
    @GetMapping("/hello")
    public String hello() {
        return "Hello Native Spring from GraalVM!";
    }
}

#!/bin/bash

# Assurez-vous d'être dans le projet Maven
mvn clean package -Pnative \
  -DskipTests \
  --batch-mode

# Exécuter
./target/graal-spring

# Dans un autre terminal
time curl -s http://localhost:8080/hello | cat
du -h target/graal-spring