The main differences between Vector and ArrayList are:

  • Synchronization:
    • Vector: Synchronized, making it thread-safe but slower in single-threaded environments.
    • ArrayList: Not synchronized, so not thread-safe but offers better performance in single-threaded scenarios.
  • Growth:
    • Vector: Doubles its size when it runs out of space.
    • ArrayList: Increases its size by 50% when it runs out of space.
  • Legacy:
    • Vector: Part of the original Java version and considered somewhat outdated.
    • ArrayList: More commonly used in modern Java applications.

In summary, use ArrayList for better performance unless thread safety is required, in which case you might consider using Vector or alternatives like CopyOnWriteArrayList.