Question

I have a number of packages in my Java web application. In some of them I use this construct:

public class Foo {
  private static Logger logger = LoggerFactory.getLogger("com.XXX");
  public void bar() {
    Foo.logger.debug("Method bar() was just called");
  }
}

Of course, it’s just an example. Everything works fine, but I don’t like the idea of logger initialization in many classes. It’s an obvious code duplication. I would like to move it to some helper class and let all other classes access it. Is it a correct idea? Or maybe there is some other “best practice” or a pattern?

Answer 1

You could write your own utility class which wraps the global logger and implements static delegates to the logger methods. Then just do a static import of this class:

public class MyLogger {
  private static Logger logger = LoggerFactory.getLogger("application");

  public static void debug(String s) {logger.debug(s));}

  public static void debug(Class<?> caller, String s) {
     LoggerFactory.getLogger(caller.getName()).debug(s);
  }

  // ...
}

Usage:

import static MyLogger.*;

public class Foo {
  public void bar() {
    // makes use of static import!
    debug("Method bar() was just called"); 
    debug(this.getClass(), "Method bar() was just called"); 
  }
}

Added an overloaded version of the example debug delegate which takes a class object and uses the appropriate Logger.