The Java Logging API in brief (part II)

Now I'd like to debate with you about some logging best practise.
If your log messagge would not be logged with the current settings and it contains relative expensive operation like a string concatenation, it's better to precede it with a less expensive operation like a check:

if (logger.isLoggable(Level.FINEST)) {
        logger.finest("log this: "+value);
    }

To log an exception and its stacktrace use:

try {
   // Test with an exception
   throw new Exception();
} catch (Throwable e) {
   // Log the exception
   logger.log(Level.SEVERE, "your message", e);
}

You can also you when you enter in a method and with which parameters, if you throws exception in the method and when you exit and with with return value.
This is an example:

public int myMethod(String p1, int p2) {
  log.entering(MyClass.class.getName(), "myMethod",
    new Object[] { p1, p2 });

  if (p2 < 0) {
   Exception ex = new IllegalStateException();
   log.throwing(this.getClass().getName(), "myMethod", ex);
  }
  int result = p2 * 2;
  log.exiting(MyClass.class.getName(), "myMethod", result);

  return result;
 }

Note that this approach is very intrusive and inquinates you code logic, therefore it would be better to do this using an interceptor.