What does Collections.emptySet() return?
(a) Immutable Set
(b) Mutable Set
(c) The type of Set depends on the parameter passed to the emptySet() method
(d) Null object
(a) Immutable Set
(b) Mutable Set
(c) The type of Set depends on the parameter passed to the emptySet() method
(d) Null object
Correct option is (a) Immutable Set
To explain I would say: Immutable Set is useful in multithreaded environment. One does not need to declare generic type collection. It is inferred by the context of method call.