What are the differences between Java Vector and List?

In Java, the Vector and List both are collection interfaces, and the difference between them is as follows:

1. Inheritance relationships: Vector is a class, while List is an interface. Specifically, Vector inherits from the AbstractList class, while List inherits from the Collection interface.
2. Concurrency: Vector is thread-safe, as its methods are synchronized using the synchronized keyword, making it safe to use in a multi-threaded environment. However, implementations of the List interface (such as ArrayList and LinkedList) are not thread-safe and require additional synchronization measures in a multi-threaded environment.
3. Capacity Expansion: When the number of elements in a Vector or List exceeds its current capacity, they will automatically increase their capacity. The expansion strategy for Vector is to double its current capacity each time, while the expansion strategy for List can be determined based on the specific implementation.
4. Performance: Due to Vector being thread-safe, its methods require synchronization during execution, which may result in some performance loss. In contrast, some implementations of the List interface (such as ArrayList) have higher performance without the need for synchronization.

In conclusion, the main difference lies in thread safety and performance. If you need to use it in a multi-threaded environment, Vector should be prioritized; if thread safety is not needed and you have a high performance requirement, you can choose the non-thread safe implementation class of List.