= Timer Hello World: A Camel Quarkus example
:cq-example-description: An example that uses the Camel timer component to output a Hello world message to the console

{cq-description}

TIP: Check the https://camel.apache.org/camel-quarkus/latest/first-steps.html[Camel Quarkus User guide] for prerequisites
and other general information.

== Start in the Development mode

[source,shell]
----
$ mvn clean compile quarkus:dev
----

The above command compiles the project, starts the 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.

TIP: Please refer to the Development mode section of
https://camel.apache.org/camel-quarkus/latest/first-steps.html#_development_mode[Camel Quarkus User guide] for more details.

Then look at the log output in the console. There are 2 log messages. One generated from a route defined using the Java DSL in class `TimerRoute` and
another defined using the XML DSL in `src/main/resources/routes/my-routes.xml`.

As we run the example in Quarkus Dev Mode, you can edit the source code and have live updates.
For example, try to change the default greeting message in `GreetingBean` to `Bye World`.

The log message and the period at which the timer fires can be changed by modifying configuration properties `timer.period` and
`greeting.message` in `application.properties`. You can also override the default values via the command line with JVM arguments
`-Dtimer.period=5000 -Dgreeting.message="My Custom Greeting"`

=== Package and run the application

Once you are done with developing you may want to package and run the application.

TIP: Find more details about the JVM mode and Native mode in the Package and run section of
https://camel.apache.org/camel-quarkus/latest/first-steps.html#_package_and_run_the_application[Camel Quarkus User guide]

==== JVM mode

[source,shell]
----
$ mvn clean package
$ java -jar target/quarkus-app/quarkus-run.jar
...
[io.quarkus] (main) camel-quarkus-examples-... started in 1.163s.
----

==== Native mode

IMPORTANT: Native mode requires having GraalVM and other tools installed. Please check the Prerequisites section
of https://camel.apache.org/camel-quarkus/latest/first-steps.html#_prerequisites[Camel Quarkus User guide].

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

[source,shell]
----
$ mvn clean package -Pnative
$ ./target/*-runner
...
[io.quarkus] (main) camel-quarkus-examples-... started in 0.013s.
...
----

== Feedback

Please report bugs and propose improvements via https://github.com/apache/camel-quarkus/issues[GitHub issues of Camel Quarkus] project.