Java notes polymorphism

1. What is polymorphism It can be seen from the simple name that there are many forms. In fact, it means that if you want to have polymorphism, you need to have inheritance as a foreshadowing. Inheritance is the premise of polymorphism. After a subclass inherits the parent, it can carry the character ...

Posted on Sun, 01 Mar 2020 05:42:02 -0500 by iknownothing

Personal analysis of Spring Boot source code

Familiar with Spring Boot, we all know that there are many ways to start it, such as running the main function directly, running through MVN Spring Boot: run command, running through java -jar xxx.jar command, etc. Here 'run the main function directly' to analyze the start-up of Spring Boot (although there are some differences in other ways, th ...

Posted on Sun, 01 Mar 2020 05:06:27 -0500 by Mistah Roth

Besides Thread and Runnable, do you know the third way to create threads, Callable

I believe that most students who have too many threads in mathematics know that there are three common ways to create threads. One is to inherit the Thread class, one is to implement the Runnable interface, and the last is the Callable. Today, we mainly introduce the last uncommon Callable way. 1, Why C ...

Posted on Sun, 01 Mar 2020 03:44:51 -0500 by ZibingsCoder

Spring knowledge profile configuration

Article directory Introduction introduce The steps of Spring configuration are as follows Step 1: write the Spring configuration files of the three environments as follows Step 2: configure the main configuration file of Spring Step 3: write test code Step 4: analysis of error reporting reasons sum ...

Posted on Sun, 01 Mar 2020 02:03:51 -0500 by miz_luvly@hotmail.com

Spring Boot implementation add, delete, modify and query

This project does not use the service layer and database. 1. First use java to simulate the database First, there are two pojo classesDepartment.java package com.aiguigu.springboot3web.pojo; import lombok.AllArgsConstructor; import lombok.Data; import lombok.NoArgsConstructor; import java.util.Date; ...

Posted on Sat, 29 Feb 2020 23:12:20 -0500 by Yucky

One day crash Python tutorial

1, Python Basics Python is a dynamic type language with types of objects and no types of variables. It pursues simplicity, elegance and readability. It can run line by line in the terminal, or it can be written into a large object-oriented project. Before you start writing, note that in Python 2.X, you need to start with ා coding:utf-8, and pyt ...

Posted on Sat, 29 Feb 2020 22:44:58 -0500 by carefree

The 21st day of study in Qianfeng anti war class

Qianfeng anti war class On the 20th day of Qianfeng's "anti war" study, Every life stage needs to try to play their own role, the harder the more relaxed, the stronger the luckier! Come on! 2 (toString method) write the running result of the following code class Student{ private int age; p ...

Posted on Sat, 29 Feb 2020 01:21:20 -0500 by ZaZall

Talk about skywaking's CommandService

order This paper focuses on skywalking's command service CommandService skywalking-6.6.0/apm-sniffer/apm-agent-core/src/main/java/org/apache/skywalking/apm/agent/core/commands/CommandService.java @DefaultImplementor public class CommandService implements BootService, Runnable { private static final ILog LOGGER = LogManager.getLogger(Comman ...

Posted on Sat, 29 Feb 2020 01:04:25 -0500 by djg_uk

Advanced multithreading -- AQS source code of JUC concurrent programming

1. Learning entry point Since AQS is a framework for us to use, we can see which classes of this framework depend on it. From the perspective of framework, AQS defines a set of synchronizer framework for multi-threaded access to shared resources, and many synchronization class implementations rely on it, such as the commonly used Reent ...

Posted on Sat, 29 Feb 2020 00:54:08 -0500 by GM

02-Mybatis implements CRUD operation

Mybatis implements CRUD operations related Based on the previous entry project Portal Add a method to the IUserdao interface public interface IUserDao { /** * Find all methods * @return */ List<User> findAll(); /** * Find users by id * @param id * @r ...

Posted on Fri, 28 Feb 2020 22:43:15 -0500 by tinker