Collection is a framework in java that provides a container to store and manipulate a group of objects. Or in short, it is a data structure which is used to store a group of the individual object as a single entity. Using Java collections we can achieve all the operations that we can perform on data such as searching, sorting, insertion, deletion and manipulation. The Collection interface is the root interface of the Java collections framework. There is no direct implementation of this interface. However, it is implemented through its sub-interfaces like List, Set, and Queue. For example, the ArrayList class implements the List interface which is a sub-interface of the Collection Interface. Java collection framework provides many interfaces and classes which are listed below.
6. Linked Hashset
The Java collections framework is a set of classes and interfaces that implement commonly reusable collection data structures. Although referred to as a framework, it works in a manner of a library. The collections framework provides both interfaces that define various collections and classes that implement them.