Alternate Way: The other toArray() method 3 Answers Sorted by: 16 This is because you are shadowing the appArray field in your method here: int x applicants.size () String appArray new String x appArray applicants.toArray (appArray) You create a new local variable called appArray when you should be using the appArray field you already have declared in your class.

Collections. Convert ArrayList to Byte Array Java Step-1:- To convert the list of arrays to byte we need to import some classes available in Java. Using Arrays.asList () method - Pass the required array to this method and get a List object and pass it as a parameter to the constructor of the ArrayList class.

Covert ArrayList of strings to String array We can convert an array to arraylist using following ways.

Covert ArrayList of integers to int array.

The returned array is not connected to ArrayList in any way, but keep in mind that it is a shallow copy of the elements of the ArrayList. So by passing an empty array (size 0), we’re forcing ArrayList to create a new array and return it. This was intentional because if we pass a non-empty array and it has enough room to fit all elements, ArrayList will use this array instead of creating a new one. Notice that we passed an empty array new Integer. toArray() method returns an array containing all of the elements in this list in proper sequence (from first to the last element) the runtime type of the. Thus, we have used the ArrayList size() method to create the array of the same size as the arraylist. Note: The size of the array passed as an argument should be equal or greater than the arraylist. Hence, all elements of the arraylist are stored in the array.

There is something else about the behavior of toArray(.) method you must understand. Here, we have passed an array of String type as an argument. In other words, the toArray(.) method uses the type of the argument, Integer to create another array of the same type, places all elements from ArrayList into the array in order and returns it. It is not an extension methodit is part of the ArrayList class itself.

It can be converted to an array with the ToArray method. It stores a 1-dimensional collection of elements. What’s with the weird-looking argument new Integer? The reason it is there because the type of returned array is determined using this argument. An ArrayList has similarities to an array.

Arraylist to array