Java 8 formalized this concept by requiring a functional interface to be annotated with the java.lang.FunctionalInterface annotation type, as in @FunctionalInterface.

A great deal of Java programming -- from conditional statements to iterative loops -- deals with the evaluation of true or false values. When you work with the JDK's Streams API and Lambda functions, ...

The implementation of Java 8 Lambda expressions required an introduction to a number of new interfaces with esoteric names that can be somewhat intimidating to developers without any experience in ...