Our first approach was to do the configuration programatically, something like:
//get the root logger
Logger logger = Logger.getLogger("");
//create a ConsoleHandler
Handler handler = new ConsoleHandler();
Now, this works very well in the Applet Viewer, but when you run your applet in a browser you'll get an exception, since the applet can not change the Handler configuration.
Well, there is the getAnonymusLogger() function, which is designed for use in applets. An anonymous logger would mean that we miss much of the benefits of the flexibel configuration, which is based on named loggers, but I guess it is better than nothing. But while using this method makes it possible to the the level on the Logger, you still can not configure the handler, so you will not get any logging output still.
So, we had to go for the configuration file. This is actually not so bad. You find the logging.properties file (it is under jre.lib) and configure your logging there. For console logging, you have to change the level of the ConsoleHandler (configured by default, but set to INFO level):
java.util.logging.ConsoleHandler.level = FINE
If you want logging to file, you can add the FileHandler instead:
handlers= java.util.logging.FileHandler, java.util.logging.ConsoleHandler
And of course, you turn your logging on:
com.xx.package.level = FINE
Now on my Windows PC this works both in applet viewer and in browser. But when I try the ConsoleHandler on my Mac, there is another gotcha, Bug ID 6585429 LoggerTraceListener causes infinite loop under some circumstances. On my mac the console simply loops and writes the same message over and over again. Seems like this is a known bug, and there should be a fix available, but for now we are stuck with logging to file on the Mac.