A top-level class can not be called "tightly encapsulated" unless it is declared private.

Encapsulation enhances the maintainability of the code.

A tightly encapsulated class allows fast public access to member fields.

A tightly encapsulated class allows access to data only through accessor and mutator methods.

Encapsulation usually reduces the size of the code.

A tightly encapsulated class might have mutator methods that validate data before it is loaded into the internal data model.