What method is used to add an element to an ArrayList?

The method used to add an element to an ArrayList in Java is the add() method. This method is specifically designed for adding elements to the dynamic array that underlies the ArrayList data structure. When you invoke add(), you can specify the element you want to add, and it will be appended to the end of the list if no index is specified. If you provide an index, the element is added at that specific position, and subsequent elements are shifted to the right.

The add() method is a part of the ArrayList API, and it's essential for modifying the contents of the ArrayList. It allows for both adding an element at a specific index and simply appending an element to the end of the list.

This is why the add() method is the correct choice for adding elements to an ArrayList, as it directly interfaces with the ArrayList structure and is tailored for that purpose. Other methods, like insert(), append(), and push(), do not exist within the ArrayList class as defined by the Java Collections Framework.