What is the difference between array and arraylist list the advantages

As you see in this output avg. Each time I run this code a different output is generated, sometimes Arrays has less avg. So, we can not assume that Arrays offers better performance over ArrayList or vice. Your email address will not be published. Notify me of follow-up comments by email. Notify me of new posts by email. Skip to content. MainMenu MainMenu. Previous: Collection Framework — List Interface.

Ankush April 5, am. What if we add more than one element at same index? Sanjeev Singh June 21, pm. Hi Ankush , For the first time three is added to 2nd index, but when we list. Also, if there are no cons of using ArrayLists, why didn't the Java developers replace arrays with ArrayLists?

In my mind the major advantages of using an ArrayList over a primitive array are its unconfined size, its API methods and from Java 1. An ArrayList is backed by a primitive array, so technically speaking if you wanted to maintain a whole lot code yourself, you could use a primitive array but why would you want to do that, when what you're probably looking for is provided out of the box?

Furthermore, since ArrayList is a Collection , amongst other things List etc. The disadvantage of using an ArrayList when all you need is a primitive array E.

Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Collectives on Stack Overflow. Learn more. Asked 6 years, 10 months ago. Array is strongly typed. In arrays we can store only one datatype either int, string, char etc…. Arrays belong to System. Array namespace using System;. Arraylist belongs to System. Collection namespaces using System. Once you have defined the size of the array, you cannot change the value of its size.

Therefore, a normal array in Java is a static data structure because the initial size of the array is fixed. On the other hand, ArrayList is flexible in size. You can add or remove items from the list at your convenience.

While removing items form ArrayList, we are assigning null to the index whose value is removed, and the whole index value is downgraded by one automatically. Similar goes for addition also. An array is a data structure where we can store elements of a given fixed size of a similar type. Actually, ArrayList is implemented using an array in Java. It would help if you imported java. Although ArrayList is basically based on Array, we see performance differences between them. This is because of the storage type and functionality of the ArrayList.

We see performance differences in terms of CPU time and memory utilization. Depending on the operations you are performing, the performance of Array and ArrayList will vary:. ArrayList requires more memory for storage purposes compared to an array. This is because storing similar objects require more memory than storing similar primitive type variables.

This slows down the overall performance.