The Java Collection Framework and classes

• The Java Collection Framework (JCF) is interface based. That means that each class in the collection implements one of the interfaces defined by the collection framework.
• The collection framework consists of two class hierarchies: Collection and Map.
• Collections store individual objects as elements. Maps store pairs of key objects and value objects in a way that lets you retrieve a value object based on its key.
• Although there are many classes in the Java collection framework, the most commonly used classes are the ArrayList, LinkedList, HashSet, HashMap, and TreeMap classes.