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.
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...
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 maintains the insertion order of the elements. ...
If we make ArrayList as Read-Only i.e. we can only read ArrayList and we cannot perform other operations on ArrayList like delete, replace, add by using remove(), set(), add() methods, in read-only mode or in other words we cannot perform any modification in the ArrayList during Read...
In this example, we useArrays.sort()to sort an array of integers. The output shows the array sorted in ascending order. How to Sort a List in Java WithStream.sorted() Features in Java 8included the Stream API, which provides asorted()method that returns a stream consisting of the elemen...
In Java, every ArrayList has aforEachmethod, which is one of the simplest ways to loop through all the items just like theforloop. Like the previous example, we can get the names fromModelClassusing thegetName()method. importjava.util.ArrayList;importjava.util.Arrays;importjava.util.function...
The return type of this method isObject[], it returns a converted ArrayList to an Array which contains all of the elements in the ArrayList. Java program to convert ArrayList to Array // Java program to demonstrate the example of// conversion of an ArrayList to an Array with// the help ...
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...
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...