Swift is a fantastic general purpose language, which can and has been successfully used beyond its mobile origins, from embedded through server-side systems. One of Swift’s unique strengths is its powerful native language interoperability with C and C++. Recently, the Swift project started work on integrating improved Swift/Java interoperability with the use of both JNI and the new Foreign Function and Memory APIs introduced in JDK22. In this talk we’ll deep dive into the deep integration approach taken between the language runtimes using the FMM APIs and their unique strengths but also challenges.