Pax Logging warning displayed when starting Karaf

[jbonofre]

When starting Karaf instance (simply with bin/karaf), a warning is displayed on the console:

org.ops4j.pax.logging.pax-logging-log4j2 [log4j2] ERROR : Log4J2 configuration problem: No type attribute provided for component out
2026-02-04T18:04:52.406495Z CM Configuration Updater (ManagedService Update: pid=[org.ops4j.pax.logging]) ERROR Log4J2 configuration problem: No type attribute provided for component out
org.apache.logging.log4j.core.config.ConfigurationException: No type attribute provided for component out
        at org.apache.logging.log4j.core.config.properties.PropertiesConfigurationBuilder.createComponent(PropertiesConfigurationBuilder.java:362)
        at org.apache.logging.log4j.core.config.properties.PropertiesConfigurationBuilder.processRemainingProperties(PropertiesConfigurationBuilder.java:206)
        at org.apache.logging.log4j.core.config.properties.PropertiesConfigurationBuilder.build(PropertiesConfigurationBuilder.java:190)
        at org.apache.logging.log4j.core.config.properties.PropertiesConfigurationFactory.getConfiguration(PropertiesConfigurationFactory.java:56)
        at org.ops4j.pax.logging.log4j2.internal.PaxLoggingServiceImpl.configureLog4J2(PaxLoggingServiceImpl.java:520)
        at org.ops4j.pax.logging.log4j2.internal.PaxLoggingServiceImpl.updated(PaxLoggingServiceImpl.java:341)
        at org.ops4j.pax.logging.log4j2.internal.LoggingManagedService.updated(LoggingManagedService.java:37)
        at org.apache.felix.cm.impl.helper.ManagedServiceTracker.updated(ManagedServiceTracker.java:189)
        at org.apache.felix.cm.impl.helper.ManagedServiceTracker.updateService(ManagedServiceTracker.java:152)
        at org.apache.felix.cm.impl.helper.ManagedServiceTracker.provideConfiguration(ManagedServiceTracker.java:85)
        at org.apache.felix.cm.impl.ConfigurationManager$ManagedServiceUpdate.provide(ConfigurationManager.java:1131)
        at org.apache.felix.cm.impl.ConfigurationManager$ManagedServiceUpdate.run(ConfigurationManager.java:1087)
        at org.apache.felix.cm.impl.UpdateThread.run0(UpdateThread.java:122)
        at org.apache.felix.cm.impl.UpdateThread.run(UpdateThread.java:84)
        at java.base/java.lang.Thread.run(Thread.java:829)

The default configuration has to be updated to avoid that.

[grgrzybek]

Related to:

• Error displayed when starting Karaf #2121

The fix should be on Karaf side

[jbonofre]

@grgrzybek that's a "dumb duplicate" as the miilestone is different 😄

[grgrzybek]

sure sure :) should be "related"