PMD - Jakarta Commons Logging Rules

The eleventh installation of explanation of PMD rules covering Jakarta Common Logging Rules.

Jakarta Commons Logging Rules

The Jakarta Commons Logging ruleset contains a collection of rules that find questionable usages of that framework.

UseCorrectExceptionLogging

To make sure the full stacktrace is printed out, use the logging statement with 2 arguments: a String and a Throwable.

Example

public class Main {

private static final Log _LOG = LogFactory.getLog( Main.class );

void bar() {

  try {

  } catch( Exception e ) {

   _LOG.error( e ); //Wrong!

  } catch( OtherException oe ) {

   _LOG.error( oe.getMessage(), oe ); //Correct

  }

}

}

ProperLogger

A logger should normally be defined private static final and have the correct class. Private final Log log; is also allowed for rare cases where loggers need to be passed around, with the restriction that the logger needs to be passed into the constructor.

Example

public class Foo {

// right

  private static final Log LOG = LogFactory.getLog(Foo.class);

// wrong

protected Log LOG = LogFactory.getLog(Testclass.class);

}