Why and Where to use Logging (Log4J)?

Suppose we are writing code to develop software. To track and debug our code, we typically use the statement “system.out.println(“Your message”);”. We may write this statement many times, perhaps even 100 times.

Now imagine that we have submitted the first version of our project to our client. Unfortunately, we cannot see the messages from these “system.out.println(“Your message”);” statements at runtime, so there is no way to track our software’s execution using this method. Before deploying the software on the client machine, we have to manually remove all the statements one by one. This is a time-consuming process.

Now, suppose that after some time, the client requests another functionality for the software. In this case, we have to add the “system.out.println(“Your message”);” statements again, and we need to find the exact location in the code where they should be placed. This is another time-consuming task. Furthermore, additional code for additional features means additional lines of these statements, and we have to remove them one by one again before releasing Version 2 of the software.

Another problem with using “system.out.println(“Your message”);” is that it is synchronized, making it a heavyweight operation that is expensive and time-consuming.

If we had a tool that allowed us to write log statements like “system.out.println(“Your message”);” that would display messages in the IDE console and could be disabled with a single line of code and enabled again just as easily, that would be awesome. This is where Log4j comes in, offering these features and more.

With Log4j, we can write log statements that are similar to “system.out.println(“Your message”);”, which are called logs. We can write these logs into a file, database, or other destination at runtime. We can also set log levels (there are a total of 7 different types) such as info, error, warn, debug, fatal, and trace based on the code structure and the message we want to show.

The best part of using Log4j is that it can save logs in a file or database, allowing us to track the code even during runtime. This means that if the software generates any problems when running on the client machine, we can collect the log file and easily identify the issue.

Here is a list of the reasons why you might want to use Log4j:

  • Granular logging levels: Log4j provides a range of logging levels, such as INFO, DEBUG, WARN, ERROR, and FATAL, which allow you to log information at different levels of detail.
  • Configurability: Log4j is highly configurable, allowing you to specify which loggers to use, where to write the logs, and how to format them.
  • Performance: Log4j is designed to be fast and efficient, with minimal overhead on your application’s performance.
  • Flexibility: Log4j supports a range of appenders, including console, file, and network appenders, which allow you to send logs to different destinations.
  • Integration: Log4j is widely used in the Java community, and many Java-based frameworks and applications integrate with Log4j.

To be continued…