No, it's not going to load native libs, and 'jni' almost certainly does not work as normal, nio is widespread in java depends on 'native' buffers (actually native) and is a core part of Java. This is just one of a few examples of where 'this isn't really Java'. 'Most' apps will not run out of the box in this WASM config.
Clearly several people have no idea what you’re talking about, so either you’re bad at explaining or everyone around you is an idiot. I’ll let you decide which option you think is more likely.