How do I initialize a `List<String>` object in Java?
Abdul D.
—The Problem
I don’t know how to initialize a List<String> object in Java.
The Solution
Depending on your needs and the Java version you’re using, there are multiple ways to initialize a List<String> object.
We’ll demonstrate how to use the following:
- The
ArrayListclass - The
Arrays.asList()method - The
List.of()method
Note: The List.of() method can only be used with with Java 9+.
Using ArrayList
ArrayListThe most common way to initialize a List<String> is to use an ArrayList, which is part of the java.util package:
import java.util.ArrayList; import java.util.List; public class Main { public static void main(String[] args) { List<String> myList = new ArrayList<>(); myList.add("Apple"); myList.add("Banana"); myList.add("Cherry"); System.out.println("My List: " + myList); } }
In this example, myList is an instance of ArrayList that holds String elements. The add() method adds items to the list.
Using Arrays.asList()
Arrays.asList()Alternatively, you can use Arrays.asList() to initialize a List with predefined values:
import java.util.Arrays; import java.util.List; public class Main { public static void main(String[] args) { List<String> myList = Arrays.asList("Apple", "Banana", "Cherry"); System.out.println("My List: " + myList); } }
The Arrays.asList() method creates a fixed-size list, meaning you cannot add or remove elements after initialization.
Using List.of()
List.of()If you are using Java 9 or later, you can use List.of() to create an immutable list:
import java.util.List; public class Main { public static void main(String[] args) { List<String> myList = List.of("Apple", "Banana", "Cherry"); System.out.println("My List: " + myList); } }
Lists created with the List.of() method are immutable, meaning you cannot add, remove, or modify list elements after initialization.
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