getting-started-reactive

Getting started with Quarkus

This is a minimal CRUD service exposing a couple of endpoints over REST.

Under the hood, this demo uses:

• RESTEasy to expose the REST endpoints
• REST-assured and JUnit 5 for endpoint testing

Requirements

To compile and run this demo you will need:

• JDK 17+
• GraalVM

Configuring GraalVM and JDK 17+

Make sure that both the GRAALVM_HOME and JAVA_HOME environment variables have been set, and that a JDK 17+ java command is on the path.

See the Building a Native Executable guide for help setting up your environment.

Building the application

Launch the Maven build on the checked out sources of this demo:

./mvnw package

Live coding with Quarkus

The Maven Quarkus plugin provides a development mode that supports live coding. To try this out:

./mvnw quarkus:dev

This command will leave Quarkus running in the foreground listening on port 8080.

1. Visit the default endpoint: http://127.0.0.1:8080.
   • Make a simple change to src/main/resources/META-INF/resources/index.html file.
   • Refresh the browser to see the updated page.
2. Visit the /hello endpoint: http://127.0.0.1:8080/hello
   • Update the response in src/main/java/org/acme/quickstart/GreetingResource.java. Replace hello with hello there in the hello() method.
   • Refresh the browser. You should now see hello there.
   • Undo the change, so the method returns hello again.
   • Refresh the browser. You should now see hello.

Run Quarkus in JVM mode

When you're done iterating in developer mode, you can run the application as a conventional jar file.

First compile it:

./mvnw package

Then run it:

java -jar ./target/quarkus-app/quarkus-run.jar

Have a look at how fast it boots, or measure the total native memory consumption.

Run Quarkus as a native executable

You can also create a native executable from this application without making any source code changes. A native executable removes the dependency on the JVM: everything needed to run the application on the target platform is included in the executable, allowing the application to run with minimal resource overhead.

Compiling a native executable takes a bit longer, as GraalVM performs additional steps to remove unnecessary codepaths. Use the native profile to compile a native executable:

./mvnw package -Dnative

After getting a cup of coffee, you'll be able to run this executable directly:

./target/getting-started-1.0.0-SNAPSHOT-runner