Convert List to Array in Java

The List is one of the widely used collection interfaces that is used to store the ordered collection. The List interface maintains the insertion order of elements and can store duplicate values also.

In this section, we will understand how we can convert a List into an array. In Java, we mainly have three ways to convert a List into an array which are as follows:

Using get() method of List
Using toArray() method
Using Stream in Java 8

Using get() Method

It is one of the simplest ways to convert a list into an array. In this way, we access all the list elements one by one and add them into an array.

The syntax of the get() method of the List interface is as follows:

The get() method returns the element that is located at the specified position in the list.

Let's take an example of converting a list into an array to understand how we can use the get() method of the list.

ConvertListToArrayExample1.java

import java.io.*;
import java.util.LinkedList;
import java.util.List;
// create ConvertListToArrayExample1 class to convert a list into an array
class ConvertListToArrayExample1 {
	// main() method start
	public static void main(String[] args)
	{
		 // create linked list by declaring an object of List
	     List<String> names = new LinkedList<String>();
	     // use add() method of the list to add elements in the linked list
	     names.add("Paul");
	     names.add("Donal");
	     names.add("James");
	     names.add("Robert");
	     names.add("Mery");
	     // get size of list and store it into len variable
	     int len = names.size();
	     // declare and initialize array of type string to store list elements
	     String[] namesArray = new String[ len ];
	     // iterate list using for loop and add all the elements into namesArray one by one to convert names list into an array
	     for (int i = 0; i < len; i++)
	    	 namesArray[i] = names.get(i);
	     // print all the elements of the array
	     System.out.println("After converting List into an Array");
	     for (int j = 0; j < namesArray.length; j++) {
	    	 System.out.println((j+1)+" element of the array is "+namesArray[j]);
	     }
	} 
}

Output:

Using toArray() Method

It is another way of converting a list into an array. By using the toArray() method, we can easily convert a list into an array. The toArray() method returns an array having all the elements in the list. The returned array contains elements in the same sequence as the list.

The syntax of the toArray() method of the List interface is as follows:

The toArray() method either accepts an array as a parameter or no parameter, and it returns an array containing all the elements in the list.

Let's take another example of converting a list into an array to understand how we can use the toArray() method of the list.

ConvertListToArrayExample2.java

import java.io.*;
import java.util.LinkedList;
import java.util.List;
//create ConvertListToArrayExample2 class to convert a list into an array
class ConvertListToArrayExample2 {
	// main() method start
	public static void main(String[] args)
	{
		 // create linked list by declaring an object of List
	     List<String> names = new LinkedList<String>();
	     // use add() method of the list to add elements in the linked list
	     names.add("Paul");
	     names.add("Donal");
	     names.add("James");
	     names.add("Robert");
	     names.add("Mery");
	     // use toArray() method to convert a list into an array
	     String[] namesArray = names.toArray(new String[0]);
	     // print all the elements of the array
	     System.out.println("After converting List into an Array");
	     for (int j = 0; j < namesArray.length; j++) {
	    	 System.out.println((j+1)+" element of the array is "+namesArray[j]);
	     }
	} 
}

Output:

Using Stream

There is one more way of converting a List into an array, i.e., by using Stream introduced in Java8.

The syntax of the toArray() method of the List interface is as follows:

The toArray() method either accepts an array as a parameter or no parameter. It returns an array containing all the elements in the list.

Let's take another example of converting a list into an array to understand how we can use the toArray() method of the list.

ConvertListToArrayExample3.java

import java.io.*;
import java.util.LinkedList;
import java.util.List;
//create ConvertListToArrayExample3 class to convert a list into an array
class ConvertListToArrayExample3 {
	// main() method start
	public static void main(String[] args)
	{
		 // create linked list by declaring an object of List
	     List<String> names = new LinkedList<String>();
	     // use add() method of the list to add elements in the linked list
	     names.add("Paul");
	     names.add("Donal");
	     names.add("James");
	     names.add("Robert");
	     names.add("Mery");
	     // use stream() method to convert a list into an array
	     String[] namesArray = names.stream().toArray(String[] ::new);
	     // print all the elements of the array
	     System.out.println("After converting List into an Array");
	     for (int j = 0; j < namesArray.length; j++) {
	    	 System.out.println((j+1)+" element of the array is "+namesArray[j]);
	     }
	} 
}

Output:

In Java, we mostly use get() and toArray() methods for converting a list into an array. The stream() method is not efficient in comparison of get() and toArray() methods.

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