In this tutorial, we will learn about the List interface in Java and its methods.<\/p>\n\n\n\n
In Java, the List<\/code> interface is an ordered collection that allows us to store and access elements sequentially. It extends the Collection<\/code> interface.<\/p>\n\n\n\n\n\n\n\n
Classes that Implement List<\/h2>\n\n\n\n
Since List<\/code> is an interface, we cannot create objects from it.<\/p>\n\n\n\n
In order to use functionalities of the List<\/code> interface, we can use these classes:<\/p>\n\n\n\n
ArrayList<\/li>
LinkedList<\/li>
Vector<\/li>
Stack<\/li><\/ul>\n\n\n\n<\/figure>\n\n\n\n
These classes are defined in the Collections framework and implement the List<\/code> interface.<\/p>\n\n\n\n\n\n\n\n
How to use List?<\/h2>\n\n\n\n
In Java, we must import java.util.List<\/code> package in order to use List<\/code>.<\/p>\n\n\n\n
\/\/ ArrayList implementation of List\nList<String> list1 = new ArrayList<>();\n\n\/\/ LinkedList implementation of List\nList<String> list2 = new LinkedList<>();\n<\/code><\/pre>\n\n\n\n
Here, we have created objects list1<\/var> and list2<\/var> of classes ArrayList<\/code> and LinkedList<\/code>. These objects can use the functionalities of the List<\/code> interface.<\/p>\n\n\n\n\n\n\n\n
Methods of List<\/h2>\n\n\n\n
The List<\/code> interface includes all the methods of the Collection<\/code> interface. Its because Collection<\/code> is a super interface of List<\/code>.<\/p>\n\n\n\n
Some of the commonly used methods of the Collection<\/code> interface that’s also available in the List<\/code> interface are:<\/p>\n\n\n\n
add()<\/code> – adds an element to a list<\/li>
addAll()<\/code> – adds all elements of one list to another<\/li>
get()<\/code> – helps to randomly access elements from lists<\/li>
iterator()<\/code> – returns iterator object that can be used to sequentially access elements of lists<\/li>
set()<\/code> – changes elements of lists<\/li>
remove()<\/code> – removes an element from the list<\/li>
removeAll()<\/code> – removes all the elements from the list<\/li>
clear()<\/code> – removes all the elements from the list (more efficient than removeAll()<\/code>)<\/li>
size()<\/code> – returns the length of lists<\/li>
toArray()<\/code> – converts a list into an array<\/li>
contains()<\/code> – returns true<\/code> if a list contains specified element<\/li><\/ul>\n\n\n\n\n\n\n\n
Implementation of the List Interface<\/h2>\n\n\n\n
1. Implementing the ArrayList Class<\/strong><\/p>\n\n\n\n
import java.util.List;\nimport java.util.ArrayList;\n\nclass Main {\n\n public static void main(String[] args) {\n \/\/ Creating list using the ArrayList class\n List<Integer> numbers = new ArrayList<>();\n\n \/\/ Add elements to the list\n numbers.add(1);\n numbers.add(2);\n numbers.add(3);\n System.out.println(\"List: \" + numbers);\n\n \/\/ Access element from the list\n int number = numbers.get(2);\n System.out.println(\"Accessed Element: \" + number);\n\n \/\/ Remove element from the list\n int removedNumber = numbers.remove(1);\n System.out.println(\"Removed Element: \" + removedNumber);\n }\n}\n<\/code><\/pre>\n\n\n\n
![\"Classes](\"https:\/\/cdn.programiz.com\/sites\/tutorial2program\/files\/Java-list-interface.png\" "\\"Java")
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