This works because the two are closely related. In Java, nested classes are categorized as either static member classes or inner classes. Inner classes are non-static member classes, local classes ...

However, Java refers to class libraries as packages. This article explores packages; I show you how to create packages of classes and interfaces, how to import (that is, bring into a program ...

proposed in JEP 409 and available since Java 17, let developers limit and control how deeply a component's type hierarchy can extend. With sealed classes, a developer can essentially create a ...

You need a whole new class to implement a single method. Furthermore, the logic is separated from the point in which it is needed. This will make troubleshooting and code maintenance more difficult.