Convert List to Array in Java

1. Convert a List to an Array of in Java
2. Use toArray() to Convert a List to an Array of Reference Types in Java
3. Use stream() to Convert a List to an Array in Java

This tutorial discusses methods to convert a list to an array in Java.

Convert a List to an Array of in Java

This method simply creates a new array with the size same as the list and iterates over the list filling the array with elements. The below example illustrates this:

import java.util.*;
public class MyClass {
    public static void main(String args[]) {
        List<Integer> list = new ArrayList();
        list.add(1);
        list.add(2);
        int[] array = new int[list.size()];
        for(int i = 0; i < list.size(); i++) 
            array[i] = list.get(i);
    }
}

The resulting array contains all the elements from the list. Note that this method should not be used if the resulting array is of non-primitive types.

Use toArray() to Convert a List to an Array of Reference Types in Java

This method is used if the list contains elements of reference types such as objects of a class. We can use the built-in method toArray() to convert a list of such type to an array. The below example illustrates this:

import java.util.*;
public class MyClass {
    public static void main(String args[]) {
        List<Foo> list = new ArrayList();
        list.add(obj);
        Foo[] array = list.toArray(new Foo[0]);

    }
}

Use stream() to Convert a List to an Array in Java

For Java 8 and above, we can also use Stream API’s stream() method to convert a list to an array in Java. The below example illustrates this:

import java.util.*;
public class MyClass {
    public static void main(String args[]) {
        List<Integer> list = new ArrayList();
        list.add(1);
        list.add(2);
        Integer[] integers = list.stream().toArray(Integer[]::new);
    }
}