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ConcurrentHashMap is a multi-threaded version of HashMap. HashMap will have various problems during concurrent operation, such as dead circulation, data coverage and so on. These problems can be perfectly solved by using ConcurrentHashMap. Here's the problem. How does ConcurrentHashMap ensure thread safety? How is its bottom layer realized? Nex ...

HashMap is the most commonly used key value collection in java. It is necessary to understand its principle and underlying code. Today, record the of HashMap Research and analysis of put() method (element addition method); First, let's talk about the results of personal research and analysis: During instance initialization, HashMap does ...

1, Overview HashMap The general structure of the hash table is shown in the figure below. The hash table is an array. We often call each node in the array a bucket, and each node in the hash table is used to store a key value pair. When inserting elements, if there is a conflict (that is, multiple key value pairs are mapped to the same buc ...

Catalogue 1, Implementation principle of hashmap 2, Extension mechanism 2.1 When to expand capacity 2.2 how to expand capacity 3, hash algorithm Relationship between hashcode and equals 4, put and get methods of hashmap 5, The difference between hashmap and hashtable         5.1 hashmap        5.2 hashtable summary 1, Implementatio ...

MyBatis Environmental Science: JDK1.8Mysql 5.7maven 3.6.1IDEA Review: JDBCMysqlJava FoundationMavenJunit SSM framework: Configuration file. Best way: see the official website documentation; mybatis - MyBatis 3 | Getting Started 1. Introduction 1.1, What is Mybatis MyBatis is an excellent persistence framework. It supports customizing S ...

A HashMap HashTable HashSet HashMap is a hash table that stores key value mappings. It inherits from AbstractMap and implements Map, Cloneable and Serializable interfaces. The implementation of HashMap is not synchronous, which means that it is not thread safe. Its key and value can be null. The mappings in HashMap are not ordered.  &nbs ...

1. Causes The reason why I pay attention to this is a question: max-points-on-a-line on niuke.comThe title is described as follows:Given n points on a 2D plane, find the maximum number of points that lie on the same straight line.The main idea is to give me the X and Y coordinates of some points, find the line with the most points, and output ...

1, Leetccode1743 multiple processing methods On the third day, I found that the first question in the leetcode question bank was given randomly every day. Two simple questions were given to me two days ago. Today, I came directly to a medium question. Adhering to the ability to cultivate algorithmic thinking and independent thinking, I ...

HashMap first appeared in JDK 1.2, and the underlying implementation is based on hash algorithm. HashMap allows null keys and null values. When calculating the hash value of HA key, the hash value of null key is 0. HashMap does not guarantee the order of key value pairs, which means that the order of key value pairs may change after some operat ...

outline In this chapter, we learn about HashMap. We first have an overall understanding of HashMap, then learn its source code, and finally learn to use HashMap through examples. Part 1 Introduction to HashMap Introduction to HashMap HashMap is a hash table that stores key value mappings. HashMap inherits from AbstractMap and implements M ...