including the difference between classes and interfaces, see my Java 101 tutorial Working with interfaces in Java. You access an enclosed interface by prefixing its name with the enclosing ...

A callback operation in Java is one function that is passed to another function and executed after some action is completed. A callback can be executed either synchronously or asynchronously.

If you want to master functional programming, the best place to start is with the Java Function interface ... here implements Function and provides an implementation for the apply method. We could ...

As such, you can incorporate the functional Consumer interface into your code simply by creating a class that implements ... in the java.util.function package. They are regular Java interfaces that ...