1. Thread safety of ConcurrentHashMap The thread safety of ConcurrentHashMap means that the data structure of the Map will not be destroyed. For example, when performing a put operation on keys with the same hash value but not equal, it can be guaranteed that both keys are placed in the linked list (red-black binary tree) […]
Tag: concurrenthashmap
ConcurrentHashMap vs HashMap time-consuming difference in single-threaded/multi-threaded get operations
The test module of the document is expanded in the form of try -> modify -> try again -> modify again… I hope to get a result from multiple tests, but think about it carefully: the final result of the experiment is only It will be a probability result, and multiple attempts will only increase […]
Why does ConcurrentHashMap not allow null insertion?
Author: Brother Lei Source | Analysis of real Java interview questions (ID: aimianshi666) Please contact for authorization for reprinting (WeChat ID: GG_Stone) In the Java language, thread-safe collections such as ConcurrentHashMap and Hashtable do not allow key or value to be inserted into null values, while HashMap allows key or value to be inserted into […]
The underlying implementation of HashMap, LinkedHashMap, ConcurrentHashMap, ArrayList, and LinkedList.
The underlying implementation of HashMap, LinkedHashMap, ConcurrentHashMap, ArrayList, and LinkedList. HashMap related questions 1. Have you ever used HashMap? What is HashMap? Why do you use it? Used, HashMap is an asynchronous implementation of the Map interface based on hash tables. It allows null keys and null values, and HashMap relies on the design of […]
ConcurrentHashMap source code solution 2
ConcurrentHashMap source code solution 2 Red-black tree implementation explanation The red-black tree is a special balanced binary tree. It uses red and black colors to limit the height difference between the left and right sub-nodes of each node to no more than 2 times. This requires that when adding or deleting elements, adjustments must be […]
Analysis and understanding of ConcurrentHashMap and HashMap
1. HashMap HashMap used array + linked list in 1.7, and used head interpolation when hash collision occurred. Using the head insertion method is easy to cause the linked list to form a loop. Linked lists mainly solve hash collisions. If the elements on the HashMap exceed 0.75*array size, hash expansion is performed. The expansion […]
ConcurrentHashMap1.7 source code analysis
I have analyzed the structure of HashMap version 1.7, but HashMap is not thread-safe, multi-thread triggering expansion will also cause an infinite loop problem, then ConcurrentHashMap solves this problem, this is a thread-safe Map, then the corresponding internal implementation How is it? After a simple analysis, the same position as HashMap will not be repeated. […]
Part of the source code understanding of ConcurrentHashMap jdk1.8
The default initial is 16 load factor shrink size static class Node<K,V> implements Map.Entry<K,V> { final int hash; final K key; volatile V val; // This is decorated with volatile to ensure visibility during concurrency volatile Node<K,V> next; Node(int hash, K key, V val, Node<K,V> next) { this.hash = hash; this.key = key; this.val = […]
In-depth analysis of Java Map: master HashMap, TreeMap, LinkedHashMap and ConcurrentHashMap
Map interface In Java, the Map interface is a general collection of key-value pairs, which allows us to use a pair of key-values to store and access data. The key-value pair can be stored in the Map through the put(key, value) method, and then the corresponding value can be obtained through the get(key) method. Commonly […]
JDK 7 ConcurrentHashMap
Directory overview constructor analysis put process get process size calculation process Overview ConcurrentHashMap in JDK1.7 indirectly implements Map, and calls each element a segmented lock segment. Each segment is an array of HashEntry, called a table, and each element of a table is a One-way queue of HashEntry. “HashTable locks the entire container, ConcurrentHashMap locks […]