Nested classes are classes that are declared as members of other classes or scopes. Nesting classes is one way to better organize your code. For example, say you have a non-nested class (also ...

Classes, fields ... method, or constructor. Java supports four access levels: private, public, protected, and package (the default). Java provides three keywords that correspond to the first ...

Another approach could be a package-private superclass in the JDK ... and clarify the intended usage patterns for developers using the code. Sealed classes in Java represent a significant step forward ...

Java SE 15 (Sept 2020) introduces sealed classes as a preview feature ... by using a package-private constructor, and putting all the implementations in the same package. This helps, but it ...