Programmer Group

Title Description Determines whether a number n is a happy number. The definition of happy number is as follows: Starting with any positive integer, replace the number by the sum of the squares of its digits. Repeat the process until the number equals 1 (where it will stay), or it loops endlessly in a cycle which does not include 1. Those ...

JDK1.7 First, the data is stored section by section, and then each section of data is equipped with a lock. When a thread occupies the lock to access one section of data, the data of other sections can also be accessed by other threads. ConcurrentHashMap is composed of Segment array structure and HashEntry array structure. Segment is a r ...

This article is reproduced from: Implementation of HashMap in Jdk1.7 and 1.8 Essential for interview: Principles and differences of HashMap, Hashtable and ConcurrentHashMap 1, A glimpse of HashMap HashMap is a more widely used hash table implementation, and in most cases, it can carry out put and get operations under the condition of consta ...