In the java version，Table interface represents various specialized table types. Is it possible to define a simple Table struct in rust ? What about returning Box<dyn Table> instead?

Maybe we will not use dyn, when returning Box<dyn Table> has some error like error[E0404]: expected trait, found struct Table. In Rust, dyn is used for dynamic dispatch with trait objects.

Why Box<dyn Table> would give error[E0404] ? It should not when using properly.
I think in many cases, the return value of get_table needs to be downcast to a concrete type, so it makes sense to use dyn Table.
Alternatively, maybe using enum Table is feasible