In this Java 101 tutorial, I’ve explained how interfaces differ from classes, and showed you how to declare, implement, and extend interfaces in your Java programs.

In a previous Java 101 tutorial, you learned how to better organize your code by declaring reference types (also known as classes and interfaces) as members of other reference types and blocks.

java.util.function.UnaryOperator @FunctionalInterface public interface UnaryOperator<T> extends Function<T,T> T apply(T t) Applies this function to the given argument. Parameter Types: T - the input ...