Resizable-array implementation of the List interface. Implements all optional list operations, and permits all elements, including null. In addition to implementing the List interface, this class provides methods to manipulate the size of the array that is used internally to store the list.

Mar 29, 2014 · If you want to just declare it in the constructor you can have the code: ArrayList<String> name = new ArrayList<String>(); Otherwise you can declare it as a field, and then initialize it in the constructor. private ArrayList<String> name; And then in the constructor: name = new ArrayList<String>();

Mar 12, 2025 · In order to Create an ArrayList, we need to create an object of the ArrayList class. The ArrayList class consists of various constructors which allow the possible creation of the array list. The following are the constructors available in this class: This constructor is …

Aug 27, 2012 · ArrayList does not have the constructors necessary to do that. You can either wrap the arguments in a call to Arrays.asList(): new ArrayList<NPC>( Arrays.asList( new NPC("Rat", "None", 0), new NPC("Dog", "None", 0) ), or use the factory methods provided by the Guava Framework: Lists.newArrayList( new NPC("Rat", "None", 0), new NPC("Dog", "None", 0)

Feb 17, 2018 · import java.util.ArrayList; public class Team { private String name; private ArrayList<Player> team; public Team(String name) { this.name = name; //how come i have to initialize it here in the constructor to see the full list?

Apr 1, 2025 · Constructor Methods. The ArrayList class in Java provides the following constructor methods to create the ArrayList. Method #1: ArrayList() This method uses the default constructor of the ArrayList class and is used to create an empty ArrayList. The general syntax of this method is: ArrayList<data_type> list_name = new ArrayList<>();

Dec 4, 2023 · Explaining the curious case of Java’s ArrayList constructors: A simple guide for eager learners.

Oct 25, 2024 · ArrayList has three constructors which are shown below: 1. ArrayList (): The first constructor is used to builds an empty ArrayList. 2. ArrayList (Collection c): The second constructor is used to builds an array list that is initialized with the elements of the collection c. 3.

Jul 2, 2022 · In this article we saw three different constructors of the ArrayList class. public ArrayList(): This is the most popular constructor and easy to use. public ArrayList(int initialCapacity): Creates an array with specified initialCapacity in parameter.

Nov 4, 2023 · We can create an ArrayList object by using new and its constructors. There are the following constructors of the ArrayList in Java: → This creates an empty ArrayList object with a default initial capacity of “10”. If the ArrayList reaches its maximum capacity then a new ArrayList object will be created with this formula below: