mraible · Oct 27, 2026 · Oct 26, 2026 · Oct 27, 2026 · Oct 27, 2026 · Oct 27, 2026
diff --git a/.github/workflows/helidon.yml b/.github/workflows/helidon.yml
@@ -34,11 +34,11 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@v7
-      - name: Configure Java 25
+      - name: Configure Java 27
         uses: actions/setup-java@v6
         with:
           distribution: 'temurin'
-          java-version: 25
+          java-version: 27
           cache: 'gradle'
       - name: Run tests
         working-directory: ./${{ matrix.app }}

diff --git a/.github/workflows/reactive.yml b/.github/workflows/reactive.yml
@@ -49,7 +49,7 @@ jobs:
       - name: Build Helidon project
         run: |
           cd reactive/helidon
-          docker build -t helidon -f Dockerfile.native .
+          docker build -t helidon -f Dockerfile.jlink .
           docker tag helidon:latest mraible/helidon-reactive:latest
         shell: bash
 

diff --git a/README.md b/README.md
@@ -79,14 +79,14 @@ You can also build and run each example as a native app.
 - Micronaut: `./gradlew nativeCompile`
 - Quarkus: `quarkus build --native`
 - Spring Boot: `./gradlew nativeCompile`
-- Helidon: `mvn package -Pnative-image`
+- Helidon: `mvn package -Pnative-image` (imperative) or `mvn package -Pjlink-image` (reactive, which uses a jlink image because no GraalVM release supports Java 27 yet)
 
 Then, start each app as a native executable.
 
 - Micronaut: `./build/native/nativeCompile/app`
 - Quarkus: `./build/quarkus-1.0.0-SNAPSHOT-runner`
 - Spring Boot:  `./build/native/nativeCompile/spring-boot`
-- Helidon: `./target/helidon`
+- Helidon: `./target/helidon` (imperative) or `./target/helidon-jri/bin/start` (reactive)
 
 ## Links
 

diff --git a/reactive/build.sh b/reactive/build.sh
@@ -18,5 +18,6 @@ cd ../quarkus && ./gradlew build -Dquarkus.package.type=native
 echo "Building Spring Boot..."
 cd ../spring-boot && ./gradlew nativeCompile
 
-echo "Building Helidon..."
-cd ../helidon && mvn package -Pnative-image
+echo "Building Helidon (jlink image with AOT cache, requires Java 27)..."
+sdk use java 27.0.0.0+35-tem
+cd ../helidon && mvn package -Pjlink-image
diff --git a/reactive/demo.adoc b/reactive/demo.adoc
@@ -419,22 +419,17 @@ security:
 
   http :8080/hello Authorization:"Bearer $TOKEN"
 
-=== Build a native Helidon app with GraalVM
+=== Build a Helidon jlink image with an AOT cache
 
-. Update `src/main/resources/META-INF/native-image/com.example.rest/helidon/native-image.properties` so native compilation will work with Java 21.
-+
-[source,properties]
-----
-Args=--initialize-at-build-time=com.example.rest --enable-url-protocols=https
-----
+Helidon 27 requires Java 27, and no GraalVM release supports Java 27 yet, so this app uses a custom Java runtime image with an ahead-of-time (AOT) cache instead of a native executable.
 
-. Compile your Helidon app into a native executable using the `native-image` profile:
+. Build the runtime image using the `jlink-image` profile:
 
-  mvn package -Pnative-image
+  mvn package -Pjlink-image
 
 . Start your Helidon app:
 
-  ./target/helidon
+  ./target/helidon-jri/bin/start
 
 . Test your API with an access token.
 

diff --git a/reactive/helidon/Dockerfile b/reactive/helidon/Dockerfile
@@ -1,6 +1,6 @@
 
 # 1st stage, build the app
-FROM container-registry.oracle.com/java/openjdk:21 as build
+FROM container-registry.oracle.com/java/openjdk:27-oraclelinux9 AS build
 
 # Install maven
 WORKDIR /usr/share
@@ -27,7 +27,7 @@ RUN mvn package -DskipTests
 RUN echo "done!"
 
 # 2nd stage, build the runtime image
-FROM container-registry.oracle.com/java/openjdk:21
+FROM container-registry.oracle.com/java/openjdk:27-oraclelinux9
 WORKDIR /helidon
 
 # Copy the binary built in the 1st stage

diff --git a/reactive/helidon/Dockerfile.jlink b/reactive/helidon/Dockerfile.jlink
@@ -1,6 +1,6 @@
 
 # 1st stage, build the app
-FROM container-registry.oracle.com/java/openjdk:21 as build
+FROM container-registry.oracle.com/java/openjdk:27-oraclelinux9 AS build
 
 WORKDIR /usr/share
 
@@ -28,7 +28,7 @@ RUN echo "done!"
 
 # 2nd stage, build the final image with the JRI built in the 1st stage
 
-FROM debian:stretch-slim
+FROM container-registry.oracle.com/os/oraclelinux:9-slim
 WORKDIR /helidon
 COPY --from=build /helidon/target/helidon-jri ./
 ENTRYPOINT ["/bin/bash", "/helidon/bin/start"]

diff --git a/reactive/helidon/Dockerfile.native b/reactive/helidon/Dockerfile.native
diff --git a/reactive/helidon/README.md b/reactive/helidon/README.md
@@ -5,7 +5,7 @@ Sample Helidon SE project that includes multiple REST operations.
 ## Build and run
 
 
-With JDK21
+With JDK 27
 ```bash
 mvn package
 java -jar target/helidon.jar

diff --git a/reactive/helidon/pom.xml b/reactive/helidon/pom.xml
@@ -6,7 +6,7 @@
     <parent>
         <groupId>io.helidon.applications</groupId>
         <artifactId>helidon-se</artifactId>
-        <version>4.5.4</version>
+        <version>27.0.1</version>
         <relativePath/>
     </parent>
     <groupId>com.example.rest</groupId>

diff --git a/reactive/helidon/src/main/java/com/example/rest/Main.java b/reactive/helidon/src/main/java/com/example/rest/Main.java
@@ -3,6 +3,7 @@
 import com.example.rest.resource.HelloResource;
 import io.helidon.config.Config;
 import io.helidon.logging.common.LogConfig;
+import io.helidon.service.registry.Services;
 import io.helidon.webserver.WebServer;
 import io.helidon.webserver.WebServerConfig;
 import io.helidon.webserver.security.SecurityHttpFeature;
@@ -28,7 +29,7 @@ public static void main(String[] args) {
 
     static void setup(WebServerConfig.Builder server) {
         Config config = Config.create();
-        Config.global(config);
+        Services.set(Config.class, config);
 
         server.routing(routing -> routing
             .addFeature(SecurityHttpFeature.create(config.get("security.web-server")))

diff --git a/...src/main/resources/META-INF/native-image/com/example/rest/helidon/native-image.properties b/...src/main/resources/META-INF/native-image/com/example/rest/helidon/native-image.properties
diff --git a/reactive/memory.sh b/reactive/memory.sh
@@ -22,7 +22,8 @@ case "$selected_app" in
     start_command="./spring-boot/build/native/nativeCompile/spring-boot"
     ;;
   "helidon")
-    start_command="./helidon/target/helidon"
+    start_command="./helidon/target/helidon-jri/bin/start"
+    process_name="helidon-jri"
     ;;
   # Add more cases for other apps as needed
   *)
@@ -32,7 +33,7 @@ case "$selected_app" in
 esac
 
 # Extract the executable name using basename
-executable=$(basename "$start_command")
+executable=${process_name:-$(basename "$start_command")}
 
 # Define memory function
 memory() {

diff --git a/reactive/start.sh b/reactive/start.sh
@@ -21,7 +21,7 @@ case "$selected_app" in
     start_command="./spring-boot/build/native/nativeCompile/spring-boot"
     ;;
   "helidon")
-    start_command="./helidon/target/helidon"
+    start_command="./helidon/target/helidon-jri/bin/start"
     ;;
   # Add more cases for other apps as needed
   *)