April 2018
Intermediate to advanced
910 pages
33h 21m
English
As you can see from the following illustration, packages are comprised of classes and interfaces, and modules are comprised of packages. Modules are a container of packages. This is the basic premise, at a very high level, of Java 9's new modular system. It is important to view modules as part of the modular system and not simply as a new level of abstraction above packages, as the illustration might suggest.

So, modules are new to Java 9 and they, as you would expect, require declaration before they can be used. A module's declaration includes names of other modules in which it has a dependency. It ...