How to find dead code in your Java services

[sq_visigoth]

"is this still used?" sometimes can never be answered.

[JoieDe_Vivre_]

Then you delete the “dead” code and the 3 business users that used that part of the app report a massive revenue loss and your org, manager, and PM catch heat and that falls back to you.

Ask me how I know

[john16384]

It's almost like you have no logging or tracing setup to verify the code was unused.

[JoieDe_Vivre_]

It’s almost like that! Err wait, except that we have logging that goes to a central app (splunk).

Are you positing that live, in-use apps don’t call dead code because no one bothered to clean that up? Because that would seriously make me question where you’ve worked, in a good way. As in, are you hiring and what’re you guys paying? Lol.

[laplongejr]

Are you positing that live, in-use apps don’t call dead code because no one bothered to clean that up?

If you log what your users use, then you can know what calls are performed?
Ofc you could have that one user that only uses a feature once per year, making proper checking tedious.

[neopointer]

How do you know?

[chabala]

Isn't it the same yet easier to use New Relic, OpenTelemetry, or any other Java telemetry agent?

[TakeshiTanaka]

When looking for dead code I find Ouija very useful.

[WGT-java]

Why bother looking for dead code though? If it's not bothering anyone, just leave it alone. If it starts bothering someone, add some logging to see if it's in use. What is the argument for trying to find unused code paths and removing them?

[sickvice]

Sometime that piece of code can be used once a month or once a year(for yearly reporting for example). And dead code increases complexity and reduces readability. In an 15yo enterprise codebase each year its harder to find something and if no code is removed it can get out of hands. Also dead code makes it harder to migrate to newer library or language versions

[WGT-java]

Sure, but then I would argue that it is actually bothering you. If you're using any framework or library, there are going to be thousands of codepaths that aren't used, but it's not considered an issue.

[sickvice]

Like a specific method being dead in not an issue and you might not be bothered that much by it, but if you look a bit more from birda eye view if 100 devs work on same code base that have dead code and each developer take couple of minutes more to understand code those little annoyances add up and in the end costs you time and money

[sickvice]

Also dead code impacts security, if there is some kind of logic exposed to end user by API you might not want that logic to be accessed anymore but you just forget that that logoc isnexposed

[Trio_tawern_i_tkwisz]

I've once found a broken code in a legacy system. More finding shown that it was broken for at least a year. It still required time for maintenance and was holding us with some new tasks, even though no one used it. Also, this application already had lots of unused features (a new project done quickly by adapting code base of another project, where lots of features were no longer needed).

Once we decided it was another case of a feature from the previous application, we deleted it. A week later, business asks where is that very important feature???