LinkedList toArray() Method in Java (original) (raw)

Last Updated : 10 Mar, 2025

In Java, the **toArray() method is used to convert a LinkedList into an Array. It returns the same LinkedList elements but in the form of an Array only.

**Example: Here, we use toArray() to **convert a LinkedList into an Array of Integer.

Java `

// Java Program to Demonstrate how to use toArray() method // to convert a LinkedList into an array of Integer elements import java.util.LinkedList;

class Geeks { public static void main(String[] args) { // Creating an empty LinkedList of Integers LinkedList l = new LinkedList();

    // Use add() method to add elements 
    // into the LinkedList
    l.add(10);
    l.add(20);
    l.add(30);
    l.add(40);
    l.add(50);

    System.out.println("The LinkedList: " + l);

    // Creating the array
    Integer[] arr = new Integer[5];

    // using toArray() to convert 
    // linkedlist into an array
    l.toArray(arr);

    // Printing all elements of the Array
    System.out.print(
        "After converting LinkedList to Array: ");
    for (Integer element : arr) {
        System.out.print(element + " ");
    }
}

}

`

Output

The LinkedList: [10, 20, 30, 40, 50] After converting LinkedList to Array: 10 20 30 40 50

**Now there are two method to convert LinkedList into an Array i.e. one with toArray() without parameter and one with toArray(arrayName) with parameter.

1. toArray() – Without Parameter

In Java, the toArray() method without parameter returns an array containing all the elements in the list in proper sequence . The returned array will be safe as a new array is created (hence new memory is allocated). Thus the caller is free to modify the array. It acts as a bridge between array-based and collection-based APIs.

**Syntax:

Object[] toArray();

• **Parameters: It does not take any parameter.
• **Return Type: It returns an array of object containing all the elements in the list.

**Example: Here, we use toArray() **without parameter to convert a LinkedList into an Array of Integer.

Java `

// Java Program Demonstrate toArray() // method of LinkedList // without parameter (with Integer type LinkedList) import java.util.LinkedList;

public class Geeks { public static void main(String[] args) {

    // Create object of LinkedList
    LinkedList<Integer> l = new LinkedList<Integer>();

    // use add() to insert elements in a LinkedList
    l.add(1);
    l.add(2);
    l.add(3);
    l.add(4);

    System.out.println("The LinkedList is: " + l);

    // Convert LinkedList into an Array 
    // the method has no parameter
    Object[] arr = l.toArray();

    // Displaying all elements of the Array
    System.out.print(
        "After converted LinkedList to Array: ");
    for (Object i : arr)
        System.out.print(i + " ");
}

}

`

Output

The LinkedList is: [1, 2, 3, 4] After converted LinkedList to Array: 1 2 3 4

2. toArray(arrayName) – With Parameter

In Java, the toArray() method with parameter also returns an array containing all the elements in the list in proper sequence.

• If the array is larger than the LinkedList, the toArray() method fills the array with the elements from the LinkedList, and the remaining positions are filled with null.
• If the array is smaller than the LinkedList, the toArray() method creates a new array of the correct size and fills the array with the elements from the LinkedList.

**Syntax:

T[] toArray(T[] a)

• **Parameters: It takes an array as a parameter. which should be of the same type as the element of the LinkedList.
• **Return Type: It return an array containing elements similar to the LinkedList.

**Exceptions: The method might throw two types of exceptions

• **ArrayStoreException: When the mentioned array is of a different type and is not able to compare with the elements mentioned in the LinkedList.
• **NullPointerException: If the array is Null, then this exception is thrown.

**Example: Here, we use toArray(arrayName) with parameter to convert a LinkedList into an Array of String.

Java `

// Java code to Demonstrate the working of toArray(arr[]) // with parameters to convert a LinkedList into a Array of String import java.util.LinkedList;

public class Geeks{ public static void main(String args[]) { // Creating an empty LinkedList LinkedList l = new LinkedList();

    // Use add() method to insert
    // elements into the LinkedList
    l.add("Welcome");
    l.add("To");
    l.add("Geeks");
    l.add("For");
    l.add("Geeks");

    System.out.println("The LinkedList: " + l);

    // Creating the array and using toArray()
    String[] arr = new String[5];
    l.toArray(arr);

    // Displaying all elements of the Array
    System.out.print(
        "After converted LinkedList to Array: ");
    for (String e : l)
        System.out.print(e + " ");
}

}

`

Output

The LinkedList: [Welcome, To, Geeks, For, Geeks] After converted LinkedList to Array: Welcome To Geeks For Geeks