Here's how to make classes, fields, methods, constructors, and objects work together in your Java programs.

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.

To further confuse matters, every Java collection class that implements the List interface does have a size () method. Classes including Vector, Stack and ArrayList all have a size method.