Top 5 Tips on Logging in Java

In this day and age, logging is more important than ever. With Java, it’s easy to capture log files in order to record any errors or unusual circumstances or even just to get real-time info about what’s going on in the application. What exactly you gain from these logs will depend on your goals, but you’ll likely want as much information as possible.

However, basic log files are no longer enough. While a lot of Java developers use tools like logback and log4j, we should be doing more by now. You’ll need to follow the best tips and tricks to make the most of your application logs, and this guide will explain the best practices.

Top 5 Tips on Logging in Java

1. Familiarize Yourself with Logging Levels

Another key step beyond context is simply understanding the different logging levels. In Java, there are several basic logging levels: debug, info, warn, error, fetal, and off. As you might expect, they get increasingly severe. Here’s a breakdown:

Debug – This is the lowest level, and it should only be used in the Development and Testing environments, not in a Production environment.

Info – This is more restricted than debug, and it’s limited to providing more information like incoming or outgoing messages.

Warn – As you might expect, this is a warning message that an error is possible. These can be set on logging messages to warn team members.

Error – This is used to log errors and exceptions. This is a serious concern that could dramatically affect your application.

Fatal – Fatal refers to a very severe error that can lead your application to crash.
Off – This turns off logging in Java.

2. Log Everything

Using a try/catch to handle an exception is a good first step, but it can’t be your only step. Logging is like a trail of breadcrumbs you can use to arrive at errors and problems. What good is knowing about an error if you don’t have any of the contexts? Frankly, you’re missing the all-important breadcrumbs that a good log parser can extract.

What you really need to know is what was passed into the request. You need a way to see the object that was logged, as well as who the logging in user was that created it. It’s all about having the full picture so you can solve the problem quickly.

3. Use a Smart Monitoring Solution

As we mentioned before, tools like logback aren’t cutting it nowadays. You need something that works smarter and harder. When you have thousands of requests, multiple services, and so much to watch in real-time, you can’t afford not to use the best logging solution.

Papertrail is the best option that logs all your data in a single place. Your entire team can then access this data, see a logging timeline, and search for problems quickly. It’s the best way to stay on top of your application no matter what.

4. Avoid Side Effects

Do your logging statements affect your application’s behavior? One of the most common “side effect” of logging is slowing the application down. This can happen if you’re logging too much or you’re improperly using string concatenation. A good way to avoid this is by creating an upper limit of just how much you can log each hour.

5. Determine Your Logging Patterns

Finally, make sure you carefully consider your logging pattern. This is the way in which you format your logs, and it can really help when you experience errors. You might include things like the date, time, etc. However, if the date is already included in the file name, for example, there’s no reason to also include it in your pattern.

As you can see, there’s a lot to think about when determining your logging pattern. The general rule-of-thumb goes: current time (without the date), logging level, name of the thread, logger name, and message. It’s not usually needed to include the file name, class name, or even the line number. This can negatively affect the app’s performance.

Final Thoughts

These logging tips above will make your life a lot easier when it comes to the troubleshooting process. We can all be thankful for the many new logging and tracking tools that are available today. Making life easier is a must.

Take these tips above seriously if you want to see improvements in your day-to-day logging practice. With applications becoming more competitive, we all need any advantage we can get.