Java Packages
A package is a group of related classes.
Some standard packages are java.awt and java.util
To create a package, put a package declaration at the beginning of each file containing the class definitions that are to belong to the package.
public class Dodecahedron { // ...
public class Icosahedron { // ...
Nested packages are permitted. When imported, their class files must be located in subdirectories of their outer package directories.