Commons Logging (JCL)提供的是一个Java 的日志接口，同时兼顾轻量级和不依赖于具体的日志实现工具。 它提供给中间件/日志工具开发者一个简单的日志操作抽象，允许程序开发人员使用不同的具体日志实现工具。用户被假定已熟悉某种日志实现工具的更高级别的细 节。JCL提供的接口，对其它一些日志工具，包括Log4J, Avalon LogKit, and JDK 1.4等，进行了简单的包装，此接口更接近于Log4J和LogKit的实现.
Commons Logging 1.1.2 发布了，该版本主要是 bug 修复和小改动，内容包括：
Fixed Bugs:
o LOGGING-124: The jar manifest now contains proper OSGi-related metadata information. Thanks to Christian Schneider.
o LOGGING-144: LogFactory and LogFactoryImpl will not swallow certain errors anymore (ThreadDeath
and VirtualMachineError). Thanks to Sebastian Bazley.
o LOGGING-132: Jdk14Logger now correctly uses the specified logger name. Thanks to Nathan Niesen.
o LOGGING-146: Properly synchronize access to protected static field LogFactory.nullClassLoaderFactory.
Thanks to Sebastian Bazley.
o LOGGING-119: Prevent potential deadlock scenario in WeakHashtable. Thanks to Nitzan Niv, Philippe Mouawad.
o LOGGING-130: Potential missing privileged block for class loader. Thanks to Matthew P. Del Buono.
o LOGGING-145: LogFactoryImpl.setAttribute - possible NPE.
o LOGGING-142: Log4JLogger uses deprecated static members of Priority such as INFO. Thanks to Jingguo Yao.
o LOGGING-128: Static analysis suggests a number of potential improvements. Thanks to Peter Lawrey.
o LOGGING-147: SimpleLog.log - unsafe update of shortLogName.
o LOGGING-148: LogFactory.diagnosticPrefix and diagnosticsStream could be final.
Changes:
o LOGGING-135: Improved thread-safety for several log adapters, including AvalonLogger, SimpleLog,
Log4JLogger, LogKitLogger. Thanks to Sebastian Bazley.
o LOGGING-138: In case of a discovery failure now also the stacktrace of the cause will be
added to the diagnostic message. Thanks to Luke Lu.
o LOGGING-133: Change scope of Jdk14Logger.log(Level, String, Throwable) to protected, allowing
subclasses to modify the logging output. Thanks to Shevek.
