The java.util.Arrays$ArrayList is a nested class inside the Arrays class. It is a fixed size or immutable list backed by an array. Arrays.java public static <T> List<T> asList(T… a) { return new ArrayList<>(a); } /** * @serial include */ private static class ArrayList<E> extends AbstractList<E> implements RandomAccess, java.io.Serializable { private static final long serialVersionUID = […]
In Java, you can use Collections.shuffle to shuffle or randomize a ArrayList TestApp.java package com.mkyong.utils; import java.util.Arrays; import java.util.Collections; import java.util.List; public class TestApp { public static void main(String[] args) { List<String> list = Arrays.asList("A", "B", "C", "D", "1", "2", "3"); //before shuffle System.out.println(list); // again, same insert order System.out.println(list); // shuffle or randomize Collections.shuffle(list); […]
No nonsense, four ways to loop ArrayList in Java For loop For loop (Advance) While loop Iterator loop package com.mkyong.core; import java.util.ArrayList; import java.util.Iterator; import java.util.List; public class ArrayListLoopingExample { public static void main(String[] args) { List<String> list = new ArrayList<String>(); list.add("Text 1"); list.add("Text 2"); list.add("Text 3"); System.out.println("#1 normal for loop"); for (int i = […]
By default, the ArrayList’s elements are display according to the sequence it is put inside. Often times, you may need to sort the ArrayList to make it alphabetically order. In this example, it shows the use of Collections.sort(‘List’) to sort an ArrayList. import java.util.ArrayList; import java.util.Collections; import java.util.List; public class SortArrayList{ public static void main(String […]
Here’s a few ways to initialize an java.util.ArrayList, see the following full example: InitArrayList.java package com.mkyong.examples; import java.util.ArrayList; import java.util.Arrays; import java.util.List; public class InitArrayList { public static void main(String[] args) { //1. Normal way List<String> list = new ArrayList<String>(); list.add("String A"); list.add("String B"); list.add("String C"); System.out.println("List 1……"); for (String temp : list) { System.out.println(temp); […]
Collection object has a constructor that accept a Collection object to initial the value. Since both Set and List are extend the Collection, the conversion is quite straightforward. It’s just pass a List into Set constructor or vice verse. Convert List to Set Set set = new HashSet(list); Convert Set to List List list = […]
