Foreign Function and Memory APIs and Swift/Java interoperability

on YouTube ↗24m

" summary

Concrete interoperability work connects Swift and Java using Foreign Function and Memory API (JDK22) with a JNI fallback, plus a jextract-swift generator that emits Java wrappers and Swift glue. It derives Swift type metadata and value witness table sizes at runtime to allocate dense structs, exposes initializers via C-calling-convention shims, and uses arena-based lifetimes (try-with-resources or GC-backed arenas) to keep memory-safe reference counting and predictable destruction. Early, experimental, server- and Android-focused; Java 25 is the targeted stable FFM release.

AI-written summary · about

" chapters (9)

1. 0:00Swift/Java interoperability
2. 2:54Foreign Function and Memory APIs
3. 6:06Java calling Swift
4. 9:55Handling Swift types
5. 12:28Initializing Swift types from Java
6. 16:23Swift memory layouts
7. 18:30Invoking Swift methods
8. 20:56Memory management in Swift-Java
9. 22:43Deep integration and future

" related talks

• 11mExpanding Swift/Java InteroperabilityMads Odgaard · ServerSide.swift 2025
• 40mHow Swift Runs on Android — Swift SDK for Android and KMPYu Takahashi · DroidKaigi 2026
• 41mThe Kotlin Swift boundaryRussell Wolf · Chicago Roboto 2021
• 36mSwift & InteroperabilityBen Cohen, Tony Parker · ServerSide.swift 2024
• 31mSeamless Interoperability: Harnessing JNIGen and FFIGenAkanksha Singh, Kendi J · Droidcon London 2023
• 19mWhat's up with Swift 5Bas Broek · FrenchKit 2017
• 49mState of Swift Internals: Swift 4 & 5Stephen Tramer · 360iDev 2018
• 33mKotlin Multiplatform Alchemy: Making Gold out of Your Swift InteropPamela Hill · AndroidMakers by droidcon 2025