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.

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.

JDK 7 introduces a new player to this dynamic/runtime inspection, the method handle (i.e. a subclass of the abstract class java.dyn.MethodHandle).