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.<clinit> 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.GLOBAL_LOGGER_NAME). 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.GLOBAL_LOGGER_NAME) 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
