java.util.function package
Java 8 introduced new package and introduced many functional interface. It can be divided into four categories.
- Predicate
- Consumer
- Function
- Supplier
Predicate
It represents a boolean-valued function of one argument. It is a functional interface with method test(T) where T is typed.
You can see the usage here.
Consumer
It represents an operation accept(s) argument(s) and return void with side-effects. Java 8 introduced many versions of Consumers.
- Consumer
- BiConsumer
- DoubleConsumer
- ObjIntConsumer
You can see the usage of Consumer here.