Abstract classes and interfaces in Java serve fundamentally ... class when you need to implement mutable state. As an example, the Java Collections Framework includes the AbstractList class ...

If you want to master functional programming, the best place to start is with the Java Function interface. This example will show you four different ways to implement this functional interface in your ...

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 contains well over 40 different components, but ...

(See Effective Java, "Prefer interfaces to abstract classes ... or as the base type for an anonymous class. 1 This example uses a form of switch expression -- one that uses patterns as case ...