what all mean in log4j code example

Example: what is log4j

How do you use Log4J in your framework?
printing/logging the important events of the application/test run.
in my project I did logging using the log4j library.
I added the library dependency into pom.xml.
For logging we create an object from
Logger Interface and LogManager class using
getLogger method and passing the class name in it;  

private static Logger log = LogManager.getLogger(LogDemo.class.getName());
static Logger log = Logger.getLogger(log4jExample.class.getName());

We create it by passing the name of the current class.
Then we can use this object to do our logging.
log.info
log.debug
log.fatal
log.error

The Logger object is responsible for capturing 
logging information and they are stored in a namespace hierarchy.