RFR: 7184195 - java.util.logging.Logger.getGlobal().info() doesn't log without configuration (original) (raw)

Mandy Chung mandy.chung at oracle.com
Tue Oct 30 00🔞25 UTC 2012

What I mean is when multiple threads are using j.u.logging and one calls Logger.getGlobal() but the LogManager class initialization is calling Logger.getGlobal(), what will happen? similar to what the LoggingDeadlock.java test does [1]. This is the code in LogManager I'm referring to.

   // Adding the global Logger. Doing so in the Logger.<clinit>
   // would deadlock with the LogManager.<clinit>.
   Logger.getGlobal().setLogManager(manager);
   manager.addLogger(Logger.getGlobal());

Also, the logging initialization is fragile. I would suggest to verify if logging using the global logger by multiple threads print all log messages correctly.

There are several test/java/util/logging/LoggingDeadlock* tests that you should check out if they adequately verify your fix.

Mandy

[1] http://hg.openjdk.java.net/jdk8/tl/jdk/file/00cd9dc3c2b5/test/java/util/logging/LoggingDeadlock.java

On 10/29/2012 3:30 PM, Jim Gish wrote:

Hi Mandy,

I don't understand your second sentence. Could you please clarify?

Thanks, Jim On 10/29/2012 06:05 PM, Mandy Chung wrote: Jim,

The logging deadlock issue is subtle and complex. Do we have a test case that verifies your fix that is deadlock-free? I can't tell for sure but looks like it smells the potential deadlock if Logger.getGlobal() triggers the LogManager class initialization but LogManager. calls Logger.getLogger().setLogManager(). Maybe you already see this - 4994705 may give you some idea of the deadlock problem. Hope this helps. Mandy On 10/24/2012 4:13 PM, Jim Gish wrote: Please review http://cr.openjdk.java.net/~jgish/Bug7184195-global-logger-init-fix/

In JDK7, Logger.global was deprecated because of potential deadlock problems. The method getGlobal() was introduced as a convenience method to get the global logger in lieu of this or calling Logger.getLogger(Logger.GLOBALLOGGERNAME). Unfortunately, this was broken out of the gate. getGlobal() simply used the deprecated static variable global, but this had the result of returning the global logger without initializing the logging system. As a result, simply calling Logger.getGlobal().INFO("msg") does nothing. So much for the convenience of a simple global logger for devs to use ootb without any setup required. This simple fix simply returns Logger.getLogger(Logger.GLOBALLOGGERNAME) when getGlobal() is called and hence results in proper setup of the logging sytem /and /a working global logger with no "assembly" required :-) Thanks, Jim

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