Java provides a collection framework defining several groups and interfaces to represent groups of objects as a single unit.

Create packages, import packaged classes and interfaces into your programs, move packages, and encapsulate them in jar files.

Java lets you declare interfaces inside of classes. Once declared, an interface is automatically a static member of the class. There is no need to declare the interface with the static keyword.

The interfaces java.util.List and java.util.Set extend Collection, representing more specialized data structures and adding more operations and/or constraints. List represents a sequence of ...