DEX and bytecode

DEX is optimized for Android runtime execution. Reverse engineering often starts by recovering high-level structure from bytecode, then validating behavior dynamically.

APK
 ├── AndroidManifest.xml
 ├── classes.dex
 ├── resources.arsc
 ├── res/
 ├── assets/
 └── lib/
     ├── arm64-v8a/
     └── armeabi-v7a/