Mar 24, 2025 · In Java, an Array is a fixed-sized, homogenous data structure that stores elements of the same type whereas, ArrayList is a dynamic-size, part of the Java Collections Framework and is used for storing objects with built-in methods for manipulation.

Jul 3, 2024 · The most straightforward way to convert an array into an ArrayList is by using the Arrays.asList() method that creates a List view of the array, and then we create a new ArrayList using the ArrayList constructor.

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>();

Aug 26, 2015 · In your first constructor you use the default Java Constructor for creating an ArrayList that takes a collection as it's argument. (From Java Docs) public ArrayList (Collection < ? extends E > c) Constructs a list containing the elements of the specified collection, in the order they are returned by the collection's iterator.

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

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.

May 2, 2013 · Simply: you are iterating over people but you should iterate over other.people variable. Just a note: ArrayList already provides a constructor to add all items of another collection: so: is enough. other.people. Perhaps add a getPeople() / people() method that returns a copy of the list. @qkad I deleted my comment.

Oct 10, 2019 · In general, I do prefer using ArrayList over array in most cases. It cuts down on having to write as much bounds-checking or defensive programming. Typically I'll only use arrays for things like byte buffers and other low (ish) level operations. There’s already a few comments explaining the technical differences.

Difference Between Java Array vs ArrayList: 1. Nature: Arrays are static data structures in nature. This means, once declared, the size of the array cannot be altered whatsoever. Meanwhile, ArrayList is a dynamic data structure. We do not need …

May 6, 2022 · The one difference between Array and ArrayList in Java that every developer surely knows is that Array is a fixed-length data structure while ArrayList is a variable-length Collection class. It means that once an array is declared with a certain size, it …