Think in Java (14): Container in-depth study

1.HashSet set designed for quick Find
TreeSet the underlying tree structure, you must implement the comparable interface, and the deposited elements will be sorted according to the rules in the CompareTo method
Linkedhashset internally uses a linked list to maintain the insertion order of elements.

2.HASHMAP uses the object's Hashcode () for fast querying, and this method can significantly improve performance.
Linkedhashmap maintaining internal order using a linked list (insert order)
TreeMap based on the implementation of the red-black tree, the results are sorted (order determined by comparable)
Concurrenthashmap a thread-safe map

3. Why is HashMap query fast?
Because hashing is used internally: hashing makes the query fast. Use the Hashcode () method to generate a hash code

Think in Java (14): Container in-depth study