First steps

This guide outlines various ways to create a new Camel Quarkus application.

Prerequisites

  • A git client

  • An IDE

  • JDK 11+ with JAVA_HOME configured appropriately

  • Apache Maven 3.6.2+ (3.8.1 is recommended)

  • GraalVM with the native-image command installed and the GRAALVM_HOME environment variable set. See Building a native executable section of the Quarkus documentation.

  • If you are on Linux, docker is sufficient for the native mode too. Use -Pnative,docker instead of -Pnative if you choose this option.

code.quarkus.io

Projects can be generated at code.quarkus.io. All of the Camel Quarkus extensions can be found under the 'Integration' category. Use the 'search' field to help with finding extensions that you are interested in.

Simply select the component extensions that you want to work with and click the 'Generate your application' button to download a basic skeleton project. There is also the option to push the project directly to GitHub.

When the project archive download has completed successfully, unzip and import into your favorite IDE.

Maven plugin

Quarkus provides a Maven plugin that enables you to quickly bootstrap projects. For example, to create a project skeleton that includes the timer and log component extensions:

$ mvn io.quarkus:quarkus-maven-plugin:2.5.0.Final:create \
    -DprojectGroupId=org.acme \
    -DprojectArtifactId=getting-started \
    -Dextensions=camel-quarkus-log,camel-quarkus-timer

$ cd getting-started
Windows users should omit the \ if using cmd. When using Powershell, wrap the -D parameters in double quotes.

Gradle support is also available. See the Quarkus Gradle guide for more information.

IDE plugins

Quarkus has plugins for most of the popular development IDEs. They provide Quarkus language support, code / config completion, project creation wizards and much more. The plugins are available at each respective IDE marketplace.

Check the documentation of the given plugin to discover how to create projects in your preferred IDE.

Camel content assist

The following plugins provide support for content assist when editing Camel routes and application.properties:

Example projects

Camel Quarkus provides a GitHub repository containing a set of example projects.

The main branch is always aligned with the latest Camel Quarkus release.

Step by step with the rest-json example

  1. Clone the Camel Quarkus examples repository:

    $ git clone https://github.com/apache/camel-quarkus-examples.git
  2. Copy the rest-json example out of the source tree:

    $ cp -r camel-quarkus-examples/rest-json .
    $ cd rest-json
  3. Open the pom.xml file in your IDE. Change the project groupId, artifactId & version as necessary.

Explore the application code

The application has two compile dependencies:

<dependency>
    <groupId>org.apache.camel.quarkus</groupId>
    <artifactId>camel-quarkus-platform-http</artifactId>
</dependency>
<dependency>
    <groupId>org.apache.camel.quarkus</groupId>
    <artifactId>camel-quarkus-jackson</artifactId>
</dependency>

They are managed within the io.quarkus.platform:quarkus-camel-bom that is imported in <dependencyManagement>.

More about BOMs.

There are only three classes in the application: Routes defines the Camel routes, whereas Fruit and Legume are entities.

The application is configured by properties defined within src/main/resources/application.properties. E.g. the camel.context.name is set there.

Development mode

$ mvn clean compile quarkus:dev

This command compiles the project, starts your application and lets the Quarkus tooling watch for changes in your workspace. Any modifications in your project will automatically take effect in the running application.

Check the application in the browser, e.g. http://localhost:8080/fruits for the rest-json example

Then change something in the code and see the changes applied by refreshing the browser.

Please refer to Quarkus documentation for more details about the development mode.

Testing

There are two test classes in our example: RestJsonTest is for the JVM mode while RestJsonIT is there for the native mode.

The JVM mode tests are run by maven-surefire-plugin in the test Maven phase:

$ mvn clean test

This should take about 15 seconds.

The native mode tests are verified by maven-failsafe-plugin in the verify phase. Pass the native property to activate the profile that runs them:

$ mvn clean verify -Pnative

This takes about 2.5 minutes (once you have all dependencies cached).

Package and run the application

JVM mode

mvn package prepares a thin jar for running on a stock JVM:

$ mvn clean package
$ ls -lh target/quarkus-app
...
-rw-r--r--. 1 ppalaga ppalaga 238K Oct 11 18:55  quarkus-run.jar
...

You can run it as follows:

$ java -jar target/quarkus-app/quarkus-run.jar
...
[io.quarkus] (main) Quarkus started in 1.163s. Listening on: http://[::]:8080

Notice the boot time around a second.

The thin jar contains just the application code. To run it, the dependencies in target/quarkus-app/lib are required too.

Native mode

To prepare a native executable using GraalVM, run the following command:

$ mvn clean package -Pnative
$ ls -lh target
...
-rwxr-xr-x. 1 ppalaga ppalaga  46M Oct 11 18:57  my-app-0.0.1-SNAPSHOT-runner
...

Note that the runner in the listing above has no .jar extension and has the x (executable) permission set. Thus it can be run directly:

$ ./target/*-runner
...
[io.quarkus] (main) Quarkus started in 0.013s. Listening on: http://[::]:8080
...

Check how fast it started and check how little memory it consumes:

$ ps -o rss,command -p $(pgrep my-app)
  RSS COMMAND
34916 ./target/my-app-0.0.1-SNAPSHOT-runner

That’s under 35 MB of RAM!

What’s next?

We recommend to continue with Dependency management.