Not Mono, WINE. What I'm talking about is the kernel's misc. binary feature, which calls upon userland utilities to learn what to do with files marked executable but not interpreted by the shell, i.e. passed to exec(). a.out and ELF are handled directly; other executables can be handled by userland loaders if you configure it correctly. This way, you can configure the system that it passes JARs to a newly spawned JVM. And you can configure it to pass PE executables to the PE loader, which is part of WINE. And you can configure it to pass whatever Mono uses to the Mono runtimes.
I'm not sure what you mean about WINE here. Could you explain? It seems you're refering to MONO, which are the .NET, erm..., libraries? framework? stuff? written for UNIX (or maybe just Linux, not sure), led by Miguel (the 'u' is silent, goddamnit!) de Icaza IIRC.
And yes, using userspace, the JARs are run by running the JVM (Java Virtual Machine), which is the same way mono runs.