Android ART executes DEX bytecode, not Java SE class files

Android applications compile toward DEX bytecode, which the Android runtime executes on devices. This pipeline differs from standard Java SE deployment despite shared language syntax.

I treat Java language knowledge as portable, while runtime assumptions must be rechecked per platform. Class file versions, garbage collector options, and security tooling do not transfer automatically.

The runtime documentation states ART executes the DEX format and its bytecode specification.

If shared code still needs boundaries, Android Java needs explicit permission states on every device.

Share business rules across platforms, then isolate runtime and permission integration deliberately. Portability claims should name the tested runtime instead of assuming identical execution.