The Java 2 SDK organizes its vast collection of classes and interfaces into a tree-like hierarchy of packages within packages, which is equivalent to directories within directories.

Use Java's packages and static imports to organize top-level types and simplify access to their static members.

That's exactly where the sealed class comes into the picture. What is a sealed class? Sealed classes, proposed in JEP 409 and available since Java 17, let developers limit and control how deeply a ...