The difference between java collections

The difference between sets:

The difference between List, Set, and Map (Recommended learning: java course)

List allows to store duplicate objects. If it is ordered, multiple null elements can be inserted.

Set does not allow duplicate objects. If it is unordered, only one null element is allowed.

Map stores data in key-value pairs. The key is unique and can have the same value.

The difference between ArrayList, LinkedList and Vector

ArrayList is not Thread-safe, asynchronous; The data structure of dynamic array, the data growth is half by default, and the query is faster

The data structure of LinkedList is fast to add and delete, and the pointer needs to be moved

Vector is thread-safe and synchronous; data growth is doubled by default

The difference between HashMap and HashTable

HashMap thread is non-safe and non-synchronous; null keys and null value; HashMap initial capacity 16

HashTable thread-safe, synchronous; null key and null value are not allowed; Hashtable initial capacity 11

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