Java collections in detail code#

Java collections in detail code#

hashCode(): This method returns the hash code of the collection in Java.Ĩ. It returns true if they are equal, else returns false.ħ. equals(Object o): This method compares the object o with our collection for equality. This method returns true if all the elements of collection c are present in our collection, else returns false.Ħ. containsAll(collection c): This is also a boolean method. It returns true if the Object o is present in our collection, else returns false.ĥ. contains(Object o): This is a boolean method. clear(): This method removes all the elements present in our collection.Ĥ. addAll(collection c): This method is used to add all the elements of a collection c to our collection.ģ. So, every class will have its own version of this method.Ģ. Now, a list might add an object in a different way than a priority queue or a HashSet. add(Object): This method is used to add an object to the collection. Some of the methods of the collection interface are as follows.ġ. Every class implements its version of these methods. For instance, adding the data, removing the data, etc. Since this interface is implemented by all the collection classes, this interface contains those methods that are common to every collection. So, since all the classes implement the collection interface and the collection interface extends the Iterable interface, this means that all the collection classes in Java have an iterator for them. Also, all the classes implement the collection interface. The collection interface extends the Iterable interface i.e. All the classes that extend this interface are called collections in Java. There is no class named collections, but rather an interface named collection. Often there is a misconception regarding the “collections class in Java”. This interface has only one abstract method i.e. So, it provides iterators for the collections in Java. This interface, as the name suggests, provides the functionality to iterate over the collection. So, the iterable interface is the root interface of the collections framework. Now, let us clarify the concept of which interface extends which interface and who is the root among them. The iterable interface and collection interface, both considered the root interfaces. Interfaces that Extend collection Interface in Java Now, let us understand some of the most important interfaces of the Java collections framework. This is just helpful when you get stuck somewhere so that you can take help from it and analyze the hierarchy of the classes and interfaces in Java. Now, let us also see the Class Diagram of the collections framework. So, these are the 3 main entities of the collections framework in Java. For instance, we can directly sort the collection or shuffle it, etc. These are some of the methods that can be directly implemented for the implementation classes. We will learn about some of the most important classes in later sections. There are multiple important classes in the collections framework. We can use these classes and the methods of the interfaces that have been overridden in them to use in our programs. Thus these classes are often called implementation classes. The classes in Java collections framework provide the implementation for the interfaces of the collections in Java. Implementation Classes in Collections in Java We will learn some of them in detail in the later sections. There are many other interfaces in the collections framework. Some of these methods are size(), add(), remove(), etc.

This means that the methods that this interface contains, will be present in every class as every class implements this interface. the root of the hierarchy tree of the collections framework is. This means that all the methods in an interface are abstract and all the data members are final and static by default. They are like abstract classes but with complete or total abstraction. Interfaces provide a basic structure for a class in Java. Interfaces are the blueprint of classes in Java. So, let us learn a few things about each one of them.

The Java collection framework has various interfaces, classes, and algorithms. In Java, we have a collections framework to use, manipulate and play around with collections. So, the collections are the storing units or containers that group multiple items. The word ‘collections’ denotes something relating to a collection or a group. So, let us start by understanding what the collections framework is. Also, we will discuss a lot of collection programs in Java. We will discuss the basics of collections framework in Java, different collections classes, collections interfaces, etc. In this article, we are going to discuss collections in Java.