How do the operations of adding elements differ between ArrayList and LinkedList in Java?

In Java, the operations of adding elements to ArrayList and LinkedList differ in performance and internal structure:

• ArrayList uses a dynamic array. When adding an element to the end, if there is enough capacity, the operation takes amortized O(1) time. If the array is full, it expands the array (copies to a larger new array), which takes O(n).

• LinkedList is implemented as a doubly linked list. Adding an element at the beginning or end of the list takes O(1), as it only changes links. However, adding in the middle requires traversing the list to the desired position, which takes O(n).

Example:

ArrayList<String> arrayList = new ArrayList<>();
arrayList.add("element"); // adding to the end, fast if no expansion needed

LinkedList<String> linkedList = new LinkedList<>();
linkedList.addFirst("element"); // adding to the beginning, fast
linkedList.addLast("element");  // adding to the end, fast