The collection framework has several interfaces, each of which is used to store a different sort of data. The interfaces included in the framework are listed below.
* Iterable Interface : This is the collection framework's primary interface. The iterable interface is extended by the collection interface. As a result, all interfaces and classes implement this interface by default. This interface's main purpose is to provide an iterator for the collections. As a result, this interface only has one abstract method, the iterator.
* Collection Interface : The collection framework's classes implement this interface, which extends the iterable interface. This interface covers all of the basic methods that every collection has, such as adding data to the collection, removing data from the collection, clearing data, and so on. All of these methods are incorporated in this interface because they are used by all classes, regardless of their implementation style. Furthermore, including these methods in this interface guarantees that the method names are consistent across all collections. In summary, we may conclude that this interface lays the groundwork for the implementation of collection classes.
* List Interface : The collection interface has a child interface called the list interface. This interface is devoted to list data, in which we can store all of the objects in an ordered collection. This also allows for the presence of redundant data. Various classes, such as ArrayList, Vector, Stack, and others, implement this list interface. We can create a list object with any of these classes because they all implement the list.
* Queue Interface : A queue interface, as the name implies, follows the FIFO (First In First Out) order of a real-world queue line. This interface is for storing all elements in which the order of the elements is important. When we try to shop at a store, for example, the bills are issued on a first-come, first-served basis. As a result, the individual whose request is first in line receives the bill first. PriorityQueue, Deque, ArrayDeque, and other classes are available. Because all of these subclasses implement the queue, we can use any of them to create a queue object.
* Deque Interface : It differs slightly from the queue data structure. Deque, also known as a double-ended queue, is a data structure in which elements can be added and removed from both ends. The queue interface is extended by this interface. ArrayDeque is the class that implements this interface. Because this class implements the deque, we can use it to create a deque object.
* Set Interface : A set is an unordered group of objects in which duplicate values cannot be kept. This collection is utilised when we want to avoid duplication of things and only keep the ones that are unique. Various classes, such as HashSet, TreeSet, LinkedHashSet, and others, implement this set interface. We can create a set object with any of these classes because they all implement the set.
* Sorted Set Interface : This interface resembles the set interface in appearance. The only difference is that this interface provides additional methods for maintaining element ordering. The sorted set interface is an extension of the set interface that is used to manage sorted data. TreeSet is the class that implements this interface. We can create a SortedSet object using this class because it implements the SortedSet interface.
