In response to my recent blog posting Immutable Java Objects , Matt brought up a good point of discussion related to making Java classes truly immutable by declaring them as ...

Sealed classes in Java let developers limit the creation and use of subclasses and preserve the class hierarchy. Here is how sealed classes in Java work.

In Java, nested classes are categorized as either static member classes or inner classes. Inner classes are non-static member classes, local classes, or anonymous classes.