ArrayList Example with Iterators

import java.util.List;import java.util.ArrayList;import java.util.Iterator;import java.util.ListIterator;import java.util.Collections;import java.util.Random; public class ArrayListExample { public static void main(String[] args) { // ArrayList Creation List arraylistA = new ArrayList(); List arraylistB = new ArrayList(); // Adding elements to the ArrayList for (int i = 0; i < i1 =" arraylistA.iterator();"> "); while (i1.hasNext()) { System.out.print(i1.next() + " , "); } System.out.println(); System.out.print("ArrayList arraylistA --> "); for (int j = 0; j < i2 =" arraylistB.iterator();"> "); while (i2.hasNext()) { System.out.print(i2.next() + " , "); } System.out.println(); System.out.println(); System.out .println("Using ListIterator to retrieve ArrayList Elements"); System.out.println(); ListIterator li1 = arraylistA.listIterator(); // next(), hasPrevious(), hasNext(), hasNext() nextIndex() can be used with a // ListIterator interface implementation System.out.println("ArrayList arraylistA --> "); while (li1.hasNext()) { System.out.print(li1.next() + " , "); } System.out.println(); // Searching for an element in the ArrayList int index = arraylistB.indexOf("java"); System.out.println("'java' was found at : " + index); int lastIndex = arraylistB.lastIndexOf("java"); System.out.println("'java' was found at : " + lastIndex + " from the last"); System.out.println(); // Getting the subList from the original List List subList = arraylistA.subList(3, arraylistA.size()); System.out.println("New Sub-List(arraylistA) from index 3 to " + arraylistA.size() + ": " + subList); System.out.println(); // Sort an ArrayList System.out.print("Sorted ArrayList arraylistA --> "); Collections.sort(arraylistA); System.out.print(arraylistA); System.out.println(); // Reversing an ArrayList System.out.print("Reversed ArrayList arraylistA --> "); Collections.reverse(arraylistA); System.out.println(arraylistA); System.out.println(); // Checking emptyness of an ArrayList System.out.println("Is arraylistA empty? " + arraylistA.isEmpty()); System.out.println(); // Checking for Equality of ArrayLists ArrayList arraylistC = new ArrayList(arraylistA); System.out.println("arraylistA.equals(arraylistC)? " + arraylistA.equals(arraylistC)); System.out.println(); // Shuffling the elements of an ArrayList in Random Order Collections.shuffle(arraylistA, new Random()); System.out .print("ArrayList arraylistA after shuffling its elements--> "); i1 = arraylistA.iterator(); while (i1.hasNext()) { System.out.print(i1.next() + " , "); } System.out.println(); System.out.println(); // Converting an ArrayList to an Array Object[] array = arraylistA.toArray(); for (int i = 0; i < array.length; i++) { System.out.println("Array Element [" + i + "] = " + array[i]); } System.out.println(); // Clearing ArrayList Elements arraylistA.clear(); System.out.println("arraylistA after clearing : " + arraylistA); System.out.println(); }}
Output
ArrayList arraylistA --> 0 , 1 , 2 , 3 , 4 ,ArrayList arraylistA --> 0 , 1 , 2 , 3 , 4 ,ArrayList arraylistB -->beginner , java , tutorial , . , com , java , site ,
Using ListIterator to retrieve ArrayList Elements
ArrayList arraylistA -->0 , 1 , 2 , 3 , 4 ,'java' was found at : 1'java' was found at : 5 from the last
New Sub-List(arraylistA) from index 3 to 5: [3, 4]
Sorted ArrayList arraylistA --> [0, 1, 2, 3, 4]Reversed ArrayList arraylistA --> [4, 3, 2, 1, 0]
Is arraylistA empty? false
arraylistA.equals(arraylistC)? true
ArrayList arraylistA after shuffling its elements--> 3 , 2 , 1 , 0 , 4 ,
Array Element [0] = 3Array Element [1] = 2Array Element [2] = 1Array Element [3] = 0Array Element [4] = 4
arraylistA after clearing : []
Source: http://www.javabeginner.com/java-arraylist.html

Explanation:

Java ArrayList
public class ArrayListextends AbstractListimplements List, RandomAccess, Cloneable, Serializable

Resizable-array implementation of the List interface. A java ArrayList is used to store an "ordered" group of elements where duplicates are allowed.
Implements all optional list operations, and permits all elements, including null.
This class is similar to Vector, except that it is unsynchronized.
The size, isEmpty, get, set, iterator, and listIterator operations run in constant time. ArrayList's give great performance on get() and set() methods, but do not perform well on add() and remove() methods when compared to a LinkedList.
An ArrayList capacity is the size of the array used to store the elements in the list. As elements are added to an ArrayList, its capacity grows automatically. It is an Array based implementation where elements of the List can be accessed directly through get() method.
To prevent unsynchronized access to the list: List list = Collections.synchronizedList(new ArrayList(...));