Functional Interfaces in Java: Fundamentals and Examples

© Ralph Lecessi 2019

Ralph LecessiFunctional Interfaces in Javahttps://doi.org/10.1007/978-1-4842-4278-0_3

3. Predicates

Ralph Lecessi¹ 

(1)

Kendall Park, NJ, USA

 

Section 3.1: The java.util.function Package

In Java 8, the java.util.function package was added to the Java API. It contains many functional interfaces designed to assist with functional programming. These functional interfaces follow one of four basic models:

Table 3-1

Basic Models for java.util.function Interfaces

Model	Has Arguments	Returns a Value	Description
Predicate	yes	boolean	Tests argument and returns true or false.
Function	yes	yes	Maps one type to another.
Consumer	yes	no	Consumes input (returns nothing).
Supplier	no	yes	Generates output (using no input).

Many of the interfaces in the java.util.function ...