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 ...

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.

Interested in Java functional programming? The first place you need to start, especially if you use the Streams API, is with this Java Function interface example.