Initialization of log4j

Log4j is one of the most widely used logging frameworks.
The biggest question I've ever asked is why my program uses so much CPU after log4j. Is there a problem with log4j's design?

Here I put log4j common problems listed for your reference:

Log4j told me that it was not initialized correctly.

Phenomenon:
Occurs when the program is run
Log4j:no Appenders could is found for category (Some.category.name).
Log4j:please Initialize the log4j system properly.

Reason:
log4j log output requires a Appender,appender type with stdout,file,database table,syslog etc.
This error occurs if the specified logger is not and all of its ancestors are not appender.
Remember: log4j is not the default target appender.

Workaround:
The simplest is the ancestor setting of all logger appender.
Create a file under the program run Directory: log4j.properties
Content is:
Log4j.rootcategory=debug, stdout

Log4j.appender.stdout=org.apache.log4j.consoleappender
Log4j.appender.stdout.layout=org.apache.log4j.patternlayout
LOG4J.APPENDER.STDOUT.LAYOUT.CONVERSIONPATTERN=[%D{DD MMM yyyy hh:mm:ss,sss}] [%-5p] [%t] [%x] [%c] [%m]%n

And then use it in your program.
Private Category logger = Category.getroot (); Easiest

Or
Private Logger logger= Logger.getlogger (classname);

It's done.

Cond...