I presume they still have a largish runtime attached with complicates FFI especially if callbacks are involved. I've found Java FFI to generally be a pain.

Also, I think a lot of organizations would never approve using these in production, too likely that behavior will differ vs Oracle's or the OpenJDK VM's, the company won't be around in a few years, etc., and the gcj is very out of date from what I gather.

I did not mention gcj, it is a dead project since 2009.

I don't know, but I guess enterprises do trust Aicas, Aonix, IBM, Excelsior and quite a few others.

That's too terrifying to imagine.

I fail to see why.