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answered Feb 27 '23 00:00
In Java, an array is a fixed-size collection of elements of the same type, while an ArrayList is a dynamic collection that can grow or shrink in size as elements are added or removed .
Here are some of the key differences between Array and ArrayList in Java:
Size : Arrays have a fixed size that is determined at the time of declaration and cannot be changed. ArrayLists , on the other hand, can grow or shrink dynamically as elements are added or removed.
Type : Arrays can only store elements of a single type , whereas ArrayLists can store elements of any type .
Initialization : Arrays can be initialized with a specific set of values at the time of declaration, whereas ArrayLists need to be instantiated first and then elements can be added or removed as needed.
Accessing elements : Elements in an array can be accessed using their index , which is an integer value that starts at 0. In an ArrayList, elements can also be accessed using their index, but ArrayList also provides additional methods such as get() and set() to retrieve and modify elements .
Memory management : Arrays are stored in contiguous memory locations , which can make them more efficient in terms of memory usage and access speed. However, this also means that resizing an array requires allocating a new block of memory and copying the existing elements to the new location. ArrayLists , on the other hand, are implemented using a dynamically resizable array or a linked list , which can be less efficient in terms of memory usage and access speed, but allow for more flexible resizing without the need to copy the entire collection.
In general, Arrays are more suitable when the size of the collection is fixed and known at compile time, and when the collection needs to be accessed frequently using its index.