Logging Conventions

Java

• Logging framework: SLF4J (Simple Logging Facade for Java)

• Maven dependency: (version managed by our maven parent project pom.xml)

  <dependency>
  	<groupId>org.slf4j</groupId>
  	<artifactId>slf4j-api</artifactId>
  </dependency>	

• How to use: 

  // import required classes
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
   
  // define logger
  private static final Logger LOGGER = LoggerFactory.getLogger(AuthenticationServiceImpl.class);
   
  // use in code
  try {
  // logic
  } catch (final StorageException e) {
  	final String message = "(" + accountId + ") fail.";
  	LOGGER.error(message, e);
  	throw new AuthenticationServiceException(message, e);
  }

• FATAL logging level: (marker usage example)

  // import utility
  import net.bolbat.utils.logging.LoggingUtils;
   
  // use in code
  try {
  // logic
  } catch (final ManagerException e) {
  	final String message = "Can't initialize persistence service.";
  	LOGGER.error(LoggingUtils.FATAL, message, e);
  	throw new ServiceInstantiationException(message, e);
  }

• SLF4J API implementations:
  • default no-operation (NOP) logger, included in slf4j-api

  • logback: (version managed by our maven parent project pom.xml)

    maven dependency

     <dependency>
    	<groupId>ch.qos.logback</groupId>
    	<artifactId>logback-classic</artifactId>
    </dependency>

  • apache log4j: (version managed by our maven parent project pom.xml)

    maven dependency

    <dependency>
    	<groupId>org.slf4j</groupId>
    	<artifactId>slf4j-log4j12</artifactId>
    </dependency>

  • apache commons-logging: (version managed by our maven parent project pom.xml) 

    maven dependency

    <dependency>
    	<groupId>org.slf4j</groupId>
    	<artifactId>slf4j-jcl</artifactId>
    </dependency>

  • java logging (version managed by our maven parent project pom.xml) 

    maven dependency

    <dependency>
    	<groupId>org.slf4j</groupId>
    	<artifactId>slf4j-jdk14</artifactId>
    </dependency>

• How to use for JUnit's without real dependency to logger implementation

  • Add maven dependency only for testing scope (version managed by our maven parent project pom.xml) 

    logback implementation example

    <dependency>
    	<groupId>ch.qos.logback</groupId>
    	<artifactId>logback-classic</artifactId>
    	<scope>test</scope>
    </dependency>

  • Configure logger (logback example configuration)