[kelnos]

The funny thing is that Java did have green threads back in v1.1, but they were dropped in v1.3.

That doesn't invalidate your point; more than 20 years of Java practice has focused on making things work well for platform threads.

[andrewf]

I think Solaris moved from green threads to pure kernel threads at the same time (https://docs.oracle.com/cd/E19253-01/816-5137/mtintro-75924/... says Solaris 9 was the transition point).