JVM source code practice - OOP Klass model

> Github original link 1 OOP Klass (ordinary object pointer) model OOP Klass model is used to describe the properties and behaviors of class It is designed as OOP and Klass because we don't want each object to have a C ++ vtbl pointer. Therefore, ordinary oops has no virtual function Instead, they forward all "virtual" functions t ...

Posted by stopblackholes on Thu, 28 Nov 2019 20:24:27 +0100

==The difference and connection between and equals method

There are two ways to test whether two variables are equal in Java programs: One is to use the = = operator, the other is to use the equals() method. When = = is used to determine whether two variables are equal, if two variables are of basic type and both are of numerical type, true will be returned as long as the values of two ...

Posted by Sobbs on Thu, 28 Nov 2019 20:20:25 +0100

Next, jquery ajax submit the data submitted by ajax to database for query

The previous article talked about how to use jquery ajax to submit data to the background, which receives and returns it to ajax. https://www.cnblogs.com/tiezhuxiong/p/11943328.html Today, we will send the data to the database for query. Don't talk much. Take a tutorial. First, we need to establish a database:   CREATE TABLE `user` ( `id` i ...

Posted by The MA on Thu, 28 Nov 2019 20:08:45 +0100

switch; while; if exercise

Please enter the consumption amount: 500 Whether to participate in preferential exchange activities 1: 50 yuan or more, 2 yuan for Pepsi 2: 100 yuan or more, and 3 yuan for 500 ml cola 3: for 100 yuan, add 10 yuan to buy 5kg flour 4: for 200 yuan or more, add 10 yuan to buy 1 SUPOR frying pan 5: for 200 yuan, add 20 yuan to buy ...

Posted by titel on Thu, 28 Nov 2019 17:07:46 +0100

It's enough to read this article in Java multithreading (detailed summary of hematemesis)

Processes and threads A process is a dynamic execution process of a program. It needs to go through a complete process from code loading, code execution to the completion of execution. This process is also a process from the generation, development to final extinction of the process itself. The multiprocess operating system can run multiple pro ...

Posted by jasondavis on Thu, 28 Nov 2019 08:43:26 +0100

Initialization of Java static data

No matter how many objects are created in Java, static data only occupies one storage area. The following program example initializes a static storage area: //: initialization/StaticInitialization.java // Specifying initial values in a class definition. class Bowl{ // constructor Bowl(int marker){ System.out.println(" ...

Posted by ciaranmg on Wed, 27 Nov 2019 19:07:10 +0100

Sentinel - source related error customization

1. Error redirection: add build and general exception capture (increase the number of sentinel exceptions - Tracer.trace(e)) (1). Error redirection @Component public class MyUrlBlockHandler implements UrlBlockHandler { @Override public void blocked(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, BlockE ...

Posted by healy787 on Wed, 27 Nov 2019 16:00:29 +0100

java cannot get the latest inserted record when reading access database through access? JDBC 30

1. Write a circular program to read the latest row of data in the database every few seconds The method of connecting access database and the information of query. Then open a timing to remove.   package javacommon.util; import java.sql.Connection; import java.sql.DriverManager; import java.sql.PreparedStatement; import java.sql. ...

Posted by souravsasi123 on Tue, 26 Nov 2019 22:37:00 +0100

Back-end spring boot+front-end Android interaction+mysql add-delete-delete-change

1. Overview Using spring boot as the back-end framework to interact with mysql on Android, including the most basic add-delete and change functions. 2. Development environment win10 IDEA tomcat9.0.27 mysql8.0.17 spring boot 3. Backend (1) Create a new spring boot project You can see here (2)Entity Create a new User class as an entity class: p ...

Posted by mooshuligan on Tue, 26 Nov 2019 22:14:26 +0100

The use of java meta annotation @ Inherited

1. First look at the source document /** * Indicates that an annotation type is automatically inherited. If * an Inherited meta-annotation is present on an annotation type * declaration, and the user queries the annotation type on a class * declaration, and the class declaration has no annotation for this type, * then the class's supercla ...

Posted by eneyas on Tue, 26 Nov 2019 19:14:09 +0100