Using java.util.logging to log on the console

Question

I want simply to log on the console using java.util.Logging:

Logger log = Logger.getLogger("my.logger");
log.setLevel(Level.ALL);
ConsoleHandler handler = new ConsoleHandler();
handler.setFormatter(new SimpleFormatter());
log.addHandler(handler);
log.fine("hello world");

but this prints out nothing. What am I missing?

Thanks

Free

Answer 1

Very simple, a logger can have several handlers, with each a different level.

handler.setLevel(Level.ALL);

Colostrum

Which begs the question: just what is the purpose of Logger.setLevel(), if it doesn't set the levels? – Divinity

The ConsoleHandler starts with level INFO. The levels are combined. My personal opinion is that the logging API does not provide an algebra, a sensible set of combinable operations with well defined semantics. – Colostrum

the logger is used inside the class, may also be configurated by the class. the handler may be set globally. so you might have different handlers, for output to console and/or file. you definetly have different loggers, e.g. for each class. – Gatefold

@kewlbfy right: one picks a specific logger for usage, and then one dispatch to plural handlers, like for file, console, email, ticket system or whatever. – Colostrum

Answer 2

Logging on the standard System.out stream could be easily done by adding a StreamHandler handler:

logger.addHandler(new StreamHandler(System.out, new SimpleFormatter()))

Fissi

Answer 3

I'm no expert on java logging, but if you change log.fine() to log.info() it will print. There's something fishy about fine - in practice, I never used it. Hopefully somebody who knows more can answer that.

ADDED: Yes, fine is special. I found an earlier SO answer for this:

Divinity