Panama FFM Call Chain
📍 Used after slide 34-36
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Java → Arena → MemorySegment → MethodHandle → Native C++ — zero-leak by construction.
Speaker Notes
Walk-through: The flow starts at a Spring @RestController endpoint, opens a confined Arena for scoped native memory, allocates a MemorySegment, looks up the native function via SymbolLookup, and invokes it through a MethodHandle. The result is written back to a MemorySegment. When Arena.close() is called (via try-with-resources), all native memory is freed — zero leaks possible.
Key safety feature: The Arena is the breakthrough. Everything allocated in a confined arena is freed when it closes. You cannot leak native memory if you use try-with-resources. This replaces JNI’s manual memory management, which was the #1 source of native memory leaks in JVM applications.