Maven Logging

Maven uses Plexus Container logging API, like any other Plexus components, ie LoggerManager / Logger.

Starting with Maven 3.1.0, instead of implementing the API itself, Maven maps to SLF4J API's ILoggerFactory / Logger through Slf4jLoggerManager / Slf4jLogger.

Getting Logger Instance

Plexus Logger and LoggerManager can be injected in Plexus component using Plexus annotations

import org.codehaus.plexus.logging.Logger;
import org.codehaus.plexus.component.annotations.Component;
import org.codehaus.plexus.component.annotations.Requirement;

@Component( role = MyComponent.class )
public class DefaultMyComponent
    implements MyComponent
    private Logger logger;

    private LoggerManager loggerManager;

Starting with Maven 3.1.0, SLF4J Logger can be used directly too, without Plexus. Of course, this will only work when run under Maven 3.1.0, then this technique can be used safely only in Maven core components.

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

public class MyClass
   final Logger logger = LoggerFactory.getLogger( MyClass.class );

Logger Name

Before Maven 3.1.0, with logging implementation done in Maven, logger name wasn't used: they are as-is, without clear definition.

Starting with Maven 3.1.0, logging implementation can be of greatest use if logger names are well defined. This definition still needs to be defined and implemented:

  • classical "class name" pattern?
  • Maven-specific name hierarchy?
  • a mix (some with class name, some with Maven-specific hierarchy)?