Brython vs J2ObjC

Brython has no write-up on Specifiction yet; its figures are above.

J2ObjC is Google’s free, open-source command-line tool for translating Java source code into Objective-C for iOS. It is designed for sharing non-UI application logic and data models across web, Android, and iOS projects. Supported Java features include exceptions, inner and anonymous classes, generics, threads, and reflection, and the tool can translate and execute JUnit tests. The distribution contains static libraries for Guava, JUnit, Mockito, Protocol Buffers, and other Java or Android utility libraries. J2ObjC does not provide a platform-independent UI toolkit; iOS interfaces use Objective-C, Objective-C++, or Swift with Apple’s iOS SDK. Developers need source code they own or are licensed to use because Android binaries cannot be converted. Requirements include a Mac workstation, macOS 15 or higher, Xcode 16 or higher, and JDK 21 or higher. The j2objcc script wraps clang and uses the iOS SDK, while Xcode projects need J2ObjC linker settings. Objective-C reference counting leaves memory management to developers.