Overview
In general, a package can contain the following kinds of types. A package allows a developer to group classes (and interfaces) together. These classes will all be related in some way – they might all have to do with a specific application or perform a specific set of tasks. The Java API is a collection of packages – for example, the javax.xml package. The javax.xml package and its subpackages contain classes to handle XML.
Read more about this topic: Java Package