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

Joop Eggen · Accepted Answer · 2012-02-08 19:05:11Z

33

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

handler.setLevel(Level.ALL);

answered Feb 8, 2012 at 19:05

Joop Eggen

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4 Comments

user949300 Over a year ago

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

Joop Eggen Over a year ago

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.

benez Over a year ago

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.

Joop Eggen Over a year ago

@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.

kirilv · Accepted Answer · 2016-03-18 10:21:35Z

13

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

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

answered Mar 18, 2016 at 10:21

kirilv

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Comments

Community · Accepted Answer · 2017-05-23 12:16:43Z

9

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:

edited May 23, 2017 at 12:16

CommunityBot

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answered Feb 8, 2012 at 19:00

user949300

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