ProGuard and R8

Question

ProGuard

Short interview answer

ProGuard rules are now commonly consumed by R8, Android’s shrinker and optimizer. R8 can remove unused code, optimize code, and shorten identifiers; code reached through reflection needs explicit keep rules.

Detailed answer

Enable shrinking for release builds incrementally and verify affected flows. A reflective serializer may need a narrowly scoped keep rule:

-keep class com.example.api.dto.** { *; }

A rule that is too broad loses size benefits; a missing rule can break serialization, reflection, or native callbacks. Keep rules with the dependency or feature that requires them.

Sources

• Android Developers: Adopt optimizations incrementally