Check if Library is used in Android app

Question

I received some legacy code of app (not developed by me, but by some other team, with no documentation), which has almost 20+ dependencies, in build.gradle.

Answer 1

By 20+ dependencies you don't need any tooling and can do a manual check.

I would proceed like this:

1. Comment out all dependencies and check what fails (see below)
2. Uncomment the dependency that causes the failure
3. Repeat

This way you might also notice dependencies that are seldom used or can be replaced with standard libraries or other libraries that you use in the project.

Here are the things that will indicate you that a dependency is required (in the order of slowing down the feedback loop):

• compilation errors
• unit test errors
• integration / system / end-to-end / device test errors (whatever you use and call them)
• application functionality at runtime
• application performance at runtime

Runtime dependencies can be especially tricky. For example, your code might not depend on a library, but this library provides a runtime implementation for some other library you depend on. Removing such a dependency will only be visible at runtime as missing functionality or performance issues.