Depending on your application code, use one of the following approaches:

1. Create an instance of org.jboss.logging.Logger and initialize it by calling the static method Logger.getLogger(Class) for each class:

   src/main/java/org/acme/ExampleResource.java

   import org.jboss.logging.Logger; 1
   
   import javax.ws.rs.GET;
   import javax.ws.rs.Path;
   import javax.ws.rs.Produces;
   import javax.ws.rs.core.MediaType;
   
   @Path("/hello")
   public class ExampleResource {
   
       private static final Logger LOG = Logger.getLogger(ExampleResource.class); 2
   
       @GET
       @Produces(MediaType.TEXT_PLAIN)
       public String hello() {
           LOG.info("Hello"); 3
           return "hello";
       }
   }

   1. Add the org.jboss.logging.Logger import statement for each class namespace that you want to use.

   2. Add reference to the logger singleton for each class.

   3. Set a logging level for the log message.

2. Inject a configured org.jboss.logging.Logger instance in your beans and resource classes:

   src/main/java/org/acme/ExampleResource.java

   import javax.inject.Inject;
   import javax.ws.rs.GET;
   import javax.ws.rs.Path;
   import javax.ws.rs.Produces;
   import javax.ws.rs.core.MediaType;
   
   import org.jboss.logging.Logger; 1
   
   import io.quarkus.arc.log.LoggerName;
   
   @Path("/hello")
   public class ExampleResource {
   
       @Inject
       Logger log; 2
   
       @LoggerName("foo")
       Logger fooLog; 3
   
       @GET
       @Produces(MediaType.TEXT_PLAIN)
       public String hello() {
           log.info("Simple!");
           fooLog.info("Goes to foo logger!");
           return "hello";
       }
   }

   1. Add the org.jboss.logging.Logger import statement for each class namespace that you want to use.

   2. The fully qualified class name of the declaring class is used as the logger name, which is equivalent to the initialization statement org.jboss.logging.Logger.getLogger(ExampleResource.class).

   3. Set a name for the logger. In this example, the logger name is foo, which is equivalent to the initialization statement org.jboss.logging.Logger.getLogger("foo").

   The logger instances are cached internally. A logger that you inject into a bean is shared for all bean instances to avoid the possible performance penalty associated with logger instantiation.

(Optional) Configure the logging output in your application.properties file:

For example, you can create a log file and print the output to a console and the file:

quarkus.log.file.enable=true
quarkus.log.file.path=/tmp/trace.log

Run your application in development mode:

./mvnw quarkus:dev

Navigate to http://localhost:8080/hello.

Depending on your configuration, review the log messages on your terminal or in your log file.

Example output for the ExampleResource.class with logging level set to INFO:

2021-05-21 15:38:39,751 INFO  [io.quarkus] (Quarkus Main Thread) my-project my-version on JVM (powered by Quarkus 1.13.3.Final) started in 1.189s. Listening on: http://localhost:8080
2021-05-21 15:38:39,765 INFO  [io.quarkus] (Quarkus Main Thread) Profile dev activated. Live Coding activated.
2021-05-21 15:38:39,766 INFO  [io.quarkus] (Quarkus Main Thread) Installed features: [cdi, resteasy]
2021-05-21 15:38:58,790 INFO  [ExampleResource] (executor-thread-1) Hello

Add the quarkus-logging-json extension to the pom.xml file of your application:

<dependencies>
    <!-- ... your other dependencies are here ... -->
    <dependency>
      <groupId>io.quarkus</groupId>
      <artifactId>quarkus-logging-json</artifactId>
    </dependency>
  </dependencies>

(Optional) Set a profile-specific configuration for JSON logging in your application.properties file:

The following example shows how you can disable JSON logging for the development and test profiles:

%dev.quarkus.log.console.json=false
%test.quarkus.log.console.json=false