这里面包含了一百多个JAVA源文件

				See also e389 Minimizing the Impact of Logging Code. 
				    Logger logger = Logger.getLogger("com.mycompany.MyClass");
				    
				    // Check if the message will be logged
				    if (logger.isLoggable(Level.FINEST)) {
				        logger.finest("my finest message");
				    }