Modular Programming in Java 9

Rethinking Java development with packages

Think about why we use packages in Java. We could very well write entire Java applications without creating any packages and, thereby, using just the default unnamed package. It would work! However, unless it's a simple or throwaway application, that's not a good idea. The idea of packages is to group your Java types into namespaces that signify the relationship, or perhaps a common theme among those types. It makes code easier to read, understand, and navigate.

The following diagram shows an example of classes organized in packages. Adding all classes to a single package (left) is not good practice. We typically group related classes into well-named packages that describe the nature of the classes ...