Array List is part of collection framework which grow up size in nature. Array List mainly use when we wants to store dynamic objects means that A array type which is dynamic update called Dynamic Array. Array List Auto increment/decrement called resizable array implementation the List interface which have all optional list operations, and permits all elements, including null. In addition to implementing the List interface, this class provides methods to manipulate the size of the array that is used internally to store the list. Array List resize with half of size exiting list size if we add any new item when array size full then Array List Automatically grow up actual List Size/2 half of size. The main feature of Array List it is Non Synchronized in which we can run multiple task at a same time.