Java multi-threading ~ implements the singleton mode in two modes: "hungry man" and "lazy man"

content What is the singleton pattern? How to implement the singleton pattern through code? hungry man mode lazy mode Single thread version Multithreaded version double check method What is the singleton pattern? The singleton pattern is a type of design pattern. The singleton pattern means that when a class is provided for use else ...

Posted by mikeatrpi on Fri, 20 May 2022 22:24:49 +0300

JavaSE-No.8 - Polymorphism of the Three Features of Java

JavaSE Portal JavaSE_Start JavaSE-No.7.1 - Java's inheritance (super keyword) JavaSE-No.7.2 - Java's Inheritance (and Composition) content 1. The concept of polymorphism2. The realization conditions of polymorphism rewrite 3. Up and down transitions 3.1 Upward Transformation3.2 Downcasting instanceof 4. Rewritten design rules ...

Posted by Big X on Fri, 20 May 2022 00:12:51 +0300

Use of deconstruction in js (variable deconstruction, parameter deconstruction)

Deconstruction in JS **Statement: * * article taken from Crazy technology house Front end stack Sunny trees This article is a learning record based on the contents of predecessors. Deconstruction and use of variables The deconstruction of variables is mainly used to read, access and operate some attributes or values. Here are five common var ...

Posted by mark_18 on Wed, 18 May 2022 23:15:41 +0300

MyBatis learning notes - source code analysis - analysis process of configuration file

summary Continued MyBatis learning notes (IV) - source code analysis - analysis process of configuration file (I)  . In the previous article, we introduced the parsing process of properties and settings configuration. Today, we will take a look at the parsing process of other common properties, focusing on the parsing of typeAliases,envi ...

Posted by mariocesar on Wed, 18 May 2022 01:48:05 +0300

Optional makes programming more interesting

In short, Opitonal class is provided by Java. In order to solve the problem that we usually judge whether the object is empty, we will use null= The existence of obj is a headache, leading to NPE (Null Pointer Exception). At the same time, the existence of Optional can make the code simpler, more readable and more efficient General judgment: ...

Posted by xhelle on Wed, 18 May 2022 00:26:51 +0300

One click to realize automatic classification and management of files. It's really fragrant to make a visual GUI interface with Python

Often disorderly folders will make us unable to find the files we want, so I specially made a visual GUI interface to realize the filing of files by categories by one click through the input path. Like to remember collection, praise and attention. Different file suffixes are classified into different categories Let's first list some types of ...

Posted by turdferguson on Tue, 17 May 2022 23:20:41 +0300

Deep parsing resultMap tag

Generally speaking, a table corresponds to a mapper mapping file, but the storage of some attributes in the database does not directly store its contents, but stores its unique identification, such as id. the political outlook, Department, job level and position of employees in the following table are maintained through the id of each sub table ...

Posted by langemarkdesign on Tue, 17 May 2022 21:43:35 +0300

AST reverse principle analysis babel

1. What is Babel Babel is a tool chain, which is mainly used to convert code written in ECMAScript 2015 + syntax into backward compatible JavaScript syntax, so that it can run in current and old versions of browsers or other environments. Here's what Babel can do for you: grammatical transformationAdd missing features in the target environmen ...

Posted by mad3533 on Tue, 17 May 2022 04:49:43 +0300

[detailed explanation] anonymous function lambda in python

preface Lambda functions are frequently used in python. Let's learn lambda functions today. 1, lambda syntax The syntax of lambda function can only contain one statement. The format is as follows: lambda [arg1 [,arg2,...argn]]:expression lambda is the keyword reserved by python, arg1... argn is the parameter list, and expressi ...

Posted by csudhoff on Tue, 17 May 2022 02:50:19 +0300

Java: network programming

Network programming What is network programming? Network programming allows programs to interact with programs in other devices on the network. Basic mode of network communication There are two common communication modes: client server (CS) and Browser/Server(BS) Three elements of network communication Three elements overview, element 1: ...

Posted by rex9990 on Tue, 17 May 2022 01:52:38 +0300