Error displayed when starting Karaf

[jbonofre]

When starting a "fresh" Karaf vanilla (4.5.0-SNAPSHOT), a log4j error is displayed:

org.ops4j.pax.logging.pax-logging-api [log4j2] ERROR : Log4J2 configuration problem: No type attribute provided for component out
2025-10-19T12:35:09.013388Z CM Configuration Updater (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$UpdateConfiguration.run(ConfigurationManager.java:1418)
        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:840)

[grgrzybek]

Hmm, could be this:

karaf/assemblies/features/base/src/main/resources/resources/etc/org.ops4j.pax.logging.cfg

Lines 29 to 30 in 465f872

	log4j2.pattern = %d{ISO8601} | %-5p | %-16t | %-32c{1} | %X{bundle.id} - %X{bundle.name} - %X{bundle.version} | %encode{%.-500m}{CRLF}%n
	log4j2.out.pattern = \u001b[90m%d{HH:mm:ss\.SSS}\u001b[0m %highlight{%-5level}{FATAL=${color.fatal}, ERROR=${color.error}, WARN=${color.warn}, INFO=${color.info}, DEBUG=${color.debug}, TRACE=${color.trace}} \u001b[90m[%t]\u001b[0m %msg%n%throwable

but I'd have to dig deeper...

[grgrzybek]

It's caused by:

• apache/logging-log4j2@c299479
• Add option to provide URIs to monitor in addition to the config file logging-log4j2#3703

new org.apache.logging.log4j.core.config.properties.PropertiesConfigurationBuilder#processRemainingProperties() is created to process all remaining properties to search for other components.

Each property with . (dot) is treated as candidate for a component configuration, but out.pattern is not supposed to be a Log4j2 componnent.

So the fix should be to change log4j2.out.pattern to log4j2.outPattern.

[grgrzybek]

And then it works without problems:

$ bin/karaf debug
Listening for transport dt_socket at address: 5005
        __ __                  ____      
       / //_/____ __________ _/ __/      
      / ,<  / __ `/ ___/ __ `/ /_        
     / /| |/ /_/ / /  / /_/ / __/        
    /_/ |_|\__,_/_/   \__,_/_/         

  Apache Karaf (4.5.0-SNAPSHOT)

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