They are epoxied and pinned.
The more recent production uses Corby screws, where it's possible for them to do that.
Corby screws or Loveless bolts + epoxy are great on any full exposed tang.
Both mechanical and chemical attachment to the knife.
For their hidden tangs, they often (but not always) thread the tang end and bolt the handle on the knife with a pommelnut.
This is very strong when combined with epoxy.
Regards
Mikael