Quarkus Native

quarkus-native

Keyword: quarkus-native | Platforms: gemini,claude,codex

Quarkus Native Image Expert Skill - Specialized in building, optimizing, and troubleshooting native executables for Quarkus applications.

Core Mandates

• Closed-World Awareness: All classes, methods, and resources must be known at build time.
• Reflection Explicit: Register all reflection usage via @RegisterForReflection or reflection-config.json.
• Resource Registration: All runtime resources must be declared in resource-config.json.
• Build-Time Initialization: Prefer build-time initialization for faster startup; use runtime init only for side-effect classes.
• Test in Native Mode: Always run @QuarkusIntegrationTest against the native binary before production.

Quick Start: Native Build

Maven

# Build native executable
./mvnw package -Dnative

# Build in container (recommended for CI)
./mvnw package -Dnative -Dquarkus.native.container-build=true

# Build and run integration tests
./mvnw verify -Pnative

Gradle

# Build native executable
./gradlew build -Dquarkus.package.type=native

# Build in container
./gradlew build -Dquarkus.package.type=native -Dquarkus.native.container-build=true

Bazel (rules_quarkus)

# Using rules_quarkus
bazel build //:myapp_native

# With custom builder image
bazel build //:myapp_native \
  --@rules_quarkus//native:builder_image=quay.io/quarkus/ubi-quarkus-mandrel-builder-image:jdk-21

Quarkus Native Configuration

Essential Properties

# === Build Type ===
quarkus.package.type=native

# === Container Build (Recommended) ===
quarkus.native.container-build=true
quarkus.native.builder-image=quay.io/quarkus/ubi-quarkus-mandrel-builder-image:jdk-21

# === Memory ===
quarkus.native.native-image-xmx=8g

# === Debugging ===
quarkus.native.additional-build-args=-H:+ReportExceptionStackTraces

# === Reports ===
quarkus.native.enable-reports=true
# Generates: target/reports/call_tree_*.txt, target/reports/reachable_methods.txt

Profile-Specific Native Config

# application.properties
%prod.quarkus.package.type=native
%prod.quarkus.native.container-build=true
%prod.quarkus.native.builder-image=quay.io/quarkus/ubi-quarkus-mandrel-builder-image:jdk-21

# Development (JVM mode for fast startup)
%dev.quarkus.package.type=jar

# Test (native for integration tests)
%test.quarkus.package.type=native

Builder Images

Reflection Configuration

@RegisterForReflection (Recommended)

// Register a single class
@RegisterForReflection
public class UserDto {
    private String name;
    private String email;
    // getters/setters
}

// Register with specific targets
@RegisterForReflection(targets = { UserDto.class, OrderDto.class })
public class ReflectionConfig {
}

// Register all fields and methods
@RegisterForReflection(fields = false, methods = true)
public class ApiResponse {
    public String status;
    public Object data;
}

reflection-config.json

[
  {
    "name": "com.example.UserDto",
    "allDeclaredConstructors": true,
    "allPublicConstructors": true,
    "allDeclaredMethods": true,
    "allPublicMethods": true,
    "allDeclaredFields": true,
    "allPublicFields": true
  },
  {
    "name": "com.example.OrderDto",
    "methods": [
      { "name": "getId", "parameterTypes": [] },
      { "name": "setId", "parameterTypes": ["java.lang.Long"] }
    ],
    "fields": [
      { "name": "status" }
    ]
  }
]

Native Image Agent (Auto-Generate)

# Run tests with agent to auto-generate reflection config
./mvnw test -Dquarkus.native.agent.enabled=true

# Or run the application with agent
java -agentlib:native-image-agent=config-output-dir=src/main/resources/META-INF/native-image \
  -jar target/quarkus-app/quarkus-run.jar

# Merge with existing config
java -agentlib:native-image-agent=config-merge-dir=src/main/resources/META-INF/native-image \
  -jar target/quarkus-app/quarkus-run.jar

Resource Configuration

resource-config.json

{
  "resources": {
    "includes": [
      { "pattern": "\\Qapplication.properties\\E" },
      { "pattern": "\\Qdb/migration/.*\\E" },
      { "pattern": "\\QMETA-INF/.*\\E" },
      { "pattern": "\\Qtemplates/.*\\E" }
    ],
    "excludes": [
      { "pattern": "\\Q*.test\\E" }
    ]
  },
  "bundles": [
    { "name": "messages" },
    { "name": "ValidationMessages" }
  ]
}

Quarkus Resource Registration

# Register resources in application.properties
quarkus.native.resources.includes=db/migration/.*,templates/.*
quarkus.native.resources.excludes=*.test,*.dev

Initialization Configuration

Build-Time vs Runtime Initialization

# application.properties
quarkus.native.additional-build-args=\
  --initialize-at-build-time=com.example.ConfigClass,\
  --initialize-at-run-time=com.example.NetworkClient,\
  --trace-class-initialization=com.example.*

Common Initialization Patterns

// Build-time initialization (fast startup)
@io.quarkus.runtime.annotations.RegisterForReflection
public class BuildTimeConfig {
    public static final String VERSION = "1.0.0";  // Initialized at build time
}

// Runtime initialization (for classes with side effects)
public class RuntimeConfig {
    static {
        // This runs at runtime, not build time
        System.loadLibrary("native-lib");
    }
}

Profile-Guided Optimization (PGO)

Step-by-Step PGO

# Step 1: Build instrumented native binary
./mvnw package -Dnative \
  -Dquarkus.native.additional-build-args=--pgo-instrument

# Step 2: Run instrumented binary to collect profile data
./target/myapp-1.0.0-SNAPSHOT-runner
# Exercise typical workloads: API calls, database operations, etc.
# This generates: default.iprof

# Step 3: Build optimized binary with profile
./mvnw package -Dnative \
  -Dquarkus.native.additional-build-args=--pgo=default.iprof

PGO with Custom Profile Name

# Build instrumented with custom profile name
./mvnw package -Dnative \
  -Dquarkus.native.additional-build-args=--pgo-instrument=myapp.iprof

# Run and collect profile
./target/myapp-1.0.0-SNAPSHOT-runner

# Build optimized
./mvnw package -Dnative \
  -Dquarkus.native.additional-build-args=--pgo=myapp.iprof

Native Image Testing

@QuarkusIntegrationTest

@QuarkusIntegrationTest
class NativeUserResourceIT {

    @Test
    void shouldListUsers() {
        given()
            .when().get("/api/users")
            .then()
            .statusCode(200);
    }

    @Test
    void shouldCreateUser() {
        given()
            .contentType(ContentType.JSON)
            .body("{\"name\": \"Alice\", \"email\": \"alice@example.com\"}")
            .when().post("/api/users")
            .then()
            .statusCode(201);
    }
}

Conditional Native Testing

@QuarkusTest
class UserResourceTest {

    @Test
    @DisabledOnNativeImage
    void shouldTestDevOnlyFeature() {
        // Only runs in JVM mode
    }

    @Test
    @EnabledOnNativeImage
    void shouldTestNativeOnlyFeature() {
        // Only runs in native mode
    }
}

Troubleshooting Decision Tree

Native build failed?
  ├── "ClassNotFoundException" at runtime
  │     └── Missing reflection config
  │         ├── Add @RegisterForReflection to the class
  │         ├── Add to reflection-config.json
  │         └── Run with native-image agent
  ├── "NoSuchMethodException" at runtime
  │     └── Missing method in reflection config
  │         └── Add method to reflection-config.json
  ├── "MissingResourceException"
  │     └── Resource not included in native image
  │         ├── Add to resource-config.json
  │         └── Use quarkus.native.resources.includes
  ├── "UnsupportedFeatureError"
  │     └── Using unsupported JVM feature
  │         ├── Check GraalVM limitations
  │         └── Use --report-unsupported-elements-at-runtime
  ├── "OutOfMemoryError" during build
  │     └── Increase build memory
  │         └── quarkus.native.native-image-xmx=8g (or 12g)
  ├── Build timeout
  │     └── Increase timeout or use more powerful machine
  │         └── quarkus.native.additional-build-args=--timeout=600
  └── "Image build request failed"
        └── Docker/container issues
            └── Check Docker daemon, pull builder image manually

Common Errors & Fixes

Optimization Strategies

Reducing Image Size

# Remove unused beans
quarkus.native.remove-unused-beans=true

# Remove metadata for smaller image
quarkus.native.enable-reports=false

# Exclude unnecessary resources
quarkus.native.resources.excludes=*.md,*.txt

Improving Startup Time

# Use SerialGC for small heaps (default for native)
quarkus.native.additional-build-args=--gc=serial

# Or G1GC for larger heaps
quarkus.native.additional-build-args=--gc=G1

# Enable PGO for better performance
quarkus.native.additional-build-args=--pgo=default.iprof

Memory Tuning

# Set max heap for native image
quarkus.native.additional-build-args=-R:MaxHeapSize=256m

# Set initial heap
quarkus.native.additional-build-args=-R:MinHeapSize=64m

Bazel Native Build

BUILD.bazel for Native Image

load("@rules_quarkus//quarkus:defs.bzl", "quarkus_application")

quarkus_application(
    name = "myapp_native",
    srcs = glob(["src/main/java/**/*.java"]),
    resources = glob(["src/main/resources/**"]),
    deps = [
        "//common/utils",
        "@maven//:io_quarkus_quarkus_core",
        "@maven//:io_quarkus_quarkus_rest",
    ],
    native = True,
    native_image_xmx = "8g",
    additional_build_args = [
        "-H:+ReportExceptionStackTraces",
        "--initialize-at-build-time=com.example.Config",
    ],
)

References

• Quarkus Native Guide
• GraalVM Native Image
• Mandrel Documentation
• Quarkus Native Reference

Skill Interoperability

The quarkus-native skill specializes in:

• graalvm-expert 🚀: Core GraalVM Native Image knowledge.
• quarkus-expert ⚡: Quarkus-specific native build configuration.
• rules-quarkus 🔧: Bazel integration for native builds.