FFI is actually quite bad. You can't talk to native (C, C++, Go, Rust) code directly. You have to talk to Java, and if you need, from Java to Native. You also

FFI is actually quite bad. You can't talk to native (C, C++, Go, Rust) code directly. You have to talk to Java, and if you need, from Java to Native. You also communicate to Java through serialization, rather than through shared memory. Oh, and any communication goes through a Future, which is annoying.