Java Programming Language: How to Modify Elements Within an ArrayList

Hi everyone, welcome back. In this example, we will be going over how to modify elements from within an arraylist. Arraylists can be used to store a collection of data, similar to that of an array. The key difference between an arraylist and an array is that an arraylist is resizable whereas an array is not. This leaves the arraylist as a great choice when wanting to modify a collection of data. With this introduction out of the way, let’s get into it.

Creating And Populating ArrayList

Let’s start by creating and populating our arraylist. Before we can create the arraylist, we need to make sure we have our arraylist import, which is included within the java.util package:

import java.util.ArrayList;

Now, we can create and populate our arraylist:

ArrayList<String> myArrList = new ArrayList<String>();
myArrList.add("One");
myArrList.add("Two");
myArrList.add("Three");
System.out.println(myArrList);
Output:
[One, Two, Three]

We have now successfully created and populated our arraylist.

Modifying An Element

Now, let’s try to modify an element from within our arraylist. We can do this by using…