There are two ways to empty an ArrayList – By usingArrayList.clear()method or with the help ofArrayList.removeAll()method. Although both methods do the same task the way they empty the List is quite different. Lets see the below example first then we will see the implementation and differe...
In this tutorial, you will learn how to initialize an ArrayList in Java. There are several different ways to do this. Let’s discuss them with examples. 1. Basic (Normal) Initialization One of the ways to initialize anArrayListis to create it first and then add elements later usingadd()m...
// Java program to demonstrate the example of// synchronizing an ArrayList by using synchronizedList() methodimportjava.util.*;publicclassSynchronizeArrayList{publicstaticvoidmain(String[]args){// ArrayList DeclarationArrayListal=newArrayList();// By using add() method to add few elements in//Array...
In this example, we have a list of integers that we want to sort in ascending order. We use theCollections.sort()method to sort the list, and then print the sorted list to the console. The output shows the list sorted in ascending order. This is a basic way to sort a list in Jav...
Likewise, when an element is removed, it shrinks. There are no empty slots. ArrayList uses an array internally to store the elements. So you can use the zero-based index to randomly retrieve the elements. Just like the array, you can store duplicate and null values in ArrayList. ArrayList...
You can write an ArrayList object values to a plain text file in Java by using the built-in java.nio.file package. First, create your ArrayList object and add some values to the list as shown below: List arrList = new ArrayList<String>(); arrList.add("Java"); arrList.add("Programmi...
// Java program to demonstrate the example of // conversion of an ArrayList to an Array with // the help of toArray() method of ArrayList import java.util.*; public class ArrayListToArray { public static void main(String[] args) { // ArrayList Declaration ArrayList arr_list = new ...
import java.util.ArrayList;public class Main {public static void main(String[] args) {ArrayList<ModelClass> modelList;ModelClass m1 = new ModelClass();ModelClass m2 = new ModelClass();ModelClass m3 = new ModelClass();m1.setName("Sam");m2.setName("Kevin");m3.setName("Gwen");modelLis...
In Java, ArrayList can hold objects of wrapper classes like double, integer, and string. We then add elements to the ArrayList using the add() method. Firstly, we added a string value to our ArrayList, then a double value, integer, and float, respectively. We can also replace an element...
In the next example we filter a list of user objects. Main.java import java.util.ArrayList; import java.util.List; void main() { var p1 = new User("Michael", 23, Gender.MALE); var p2 = new User("Jane", 24, Gender.FEMALE); var p3 = new User("John", 44, Gender.MALE); var...