The main differences between ArrayList and LinkedList are in their internal structure and performance characteristics:

  • ArrayList:
    • Uses a dynamic array to store elements.
    • Fast random access (O(1)), but slower for insertions and deletions (O(n)).
    • Better when you need to frequently access elements by index.
  • LinkedList:
    • Uses a doubly linked list to store elements.
    • Slower random access (O(n)), but faster insertions and deletions (O(1)) at both ends.
    • Better when you need frequent insertions and deletions.

In summary, use ArrayList for quick access and LinkedList for frequent modifications.