In this post i will discuss about Log4J and Log files.

Log file is just simple file, which keep track of the record or event or info when any event happens or any software run. This whole process known as logging. We can create log file as simple log file.

Why Log file is required:

We can create log file for our simple script also so we can track or debug our script easily if anything goes wrong in script. For example, if our script is failing at some point then we can track back what went wrong

What is log4J
Log4j is free open source tool  for creating log files It help us to generate log file.

Log4j is very lightweight and simple logging framework, comprising of three main components
Loggers
Appenders
Layouts

Download Log4J jar file.

1. Navigate to http://mvnrepository.com/
2. Search for Log4J
3. Download latest version of log4J





Create a Class file with below log levels:

logger.debug("Sample debug message");
logger.info("Sample info message");
logger.warn("Sample warn message");
logger.error("Sample error message");
logger.fatal("Sample fatal message");

Below is the sample code:



After executing test you can see logs in log4j.log file and in console as well.





OUTPUT of Log4J file: