In a previous Java 101 tutorial, you learned how to better organize your code by declaring reference types (also known as classes and interfaces) as members of other reference types and blocks.

It's not very restrictive. However, rules are different from conventions. Java naming conventions for variables, methods and reference types are where things get a little more complicated. For example ...

Universal generics would allow Java type variables to range over primitive and reference types, making it easier to extend or reuse code across different types. Java would get universal generics ...

The default constructor in Java takes no arguments -- it simply initializes reference types to null and primitive types to the binary equivalent of zero. That means instance variables are assigned as ...