I have an interface that returns a class containing common classes. But where do I define the class? What I want is something like: public interface Foo { String getName(); FooType getFoo(int a ...

Functional supplier interface in Java tutorial There are only half a dozen classes you really need to master to become competent in the world of functional programming. The java.util.function package ...

The functional consumer interface is a key part of the Java Streams API. Here is a simple Consumer interface example to show you how to use this Java component.