Converting ArrayList to String[] in Java

When working with collections in Java, it may be necessary to convert an ArrayList into a String[]. This conversion is essential for scenarios where accessing the elements as an array is more appropriate or required by other functions.

Converting using toArray() Method

The toArray() method is a convenient way to convert an ArrayList to a String[]. It accepts an array as an argument, where the elements of the ArrayList are copied into. The following code snippet demonstrates the usage of toArray() method:

List list = ...;
String[] array = list.toArray(new String[0]);

In the above code, toArray() method takes an empty String array as an argument. As a result, a new String[] array is created with the same length as the ArrayList and the elements from the ArrayList are copied into the array.

Example

Consider the following example:

List list = new ArrayList();
// Add elements to the list
list.add("android");
list.add("apple");
String[] stringArray = list.toArray(new String[0]);

In this example, the ArrayList named list contains the elements "android" and "apple". The toArray() method is invoked, passing an empty String array, and the result is stored in the stringArray variable. The stringArray now contains the elements "android" and "apple".

Passing an Array as an Argument

It's important to note that the toArray() method can also be used by passing an existing array as an argument. If the passed array has sufficient size to accommodate the elements of the ArrayList, the elements will be copied into the array. Otherwise, a new array with the appropriate size will be created.