[JDK1.8 source code reading] What you should know about collections

	Arraylist	Vector	LinkedList	HashSet	LinkedHashSet	TreeSet	HashMap	LinkedHashMap	Hashtable	TreeMap
data structure	Object array	Object array	Doubly linked list	The bottom layer uses HashMap	LinkedHashSet inherits from HashSet which is implemented internally through LinkedHashMap	Red black tree	Array + linked list	LinkedHashMap inherited from HashMap (add doubly linked list)	Array + linked list	Red black tree
Thread-safe	Arraylist	Vector	LinkedList	HashSet	Non-thread safe	TreeSet	HashMap	LinkedHashMap	Hashtable	TreeMap
feature	Arraylist	Vector	LinkedList	HashSet	–	TreeSet	HashMap	Ordered doubly linked list based on HashMap	Hashtable	TreeMap
	Arraylist	Vector	LinkedList	HashSet	LinkedHashSet	TreeSet	HashMap	LinkedHashMap	Hashtable	TreeMap

List (ordered, elements can be repeated)

• Arraylist ：https://blog.csdn.net/lglglgl/article/details/105058257
• Vector ：
• LinkedList ：

Set (unordered, non-repeatable, no index)

• HashSet ：https://blog.csdn.net/lglglgl/article/details/105179591
• LinkedHashSet：https://blog.csdn.net/houyanhua1/article/details/80665314
• TreeSet：

Map

• HashMap：https://blog.csdn.net/lglglgl/article/details/105167813
• LinkedHashMap：https://www.jianshu.com/p/8f4f58b4b8ab
• Hashtable：https://blog.csdn.net/lglglgl/article/details/105145060
• TreeMap：