What is ArrayList?

Answer 1

The ArrayList class extends AbstractList and implements the List interface. ArrayList supports dynamic arrays that can grow as needed. Standard Java arrays are of a fixed length. After arrays are created, they cannot grow or shrink, which means that you must know in advance how many elements an array will hold.

Answer 2

ArrayList is used to store a collections of objects. They are flexible ( can grow and shrink when needed).

Benefits of ArrayList:

Better for accessing elements
Better for storing data
Flexibility
Etc.

Disadvantage:

Not the best for inserting data( LinkedList is better for this)

Not the best for deleting data( LinkedList is better for this)

Etc.