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summary A collection can store objects of any type. After an Object is stored in a collection, it is promoted to Object type. When I take an Object out of a collection, I need to perform mandatory transformation to operate on the Object. public static void main(String[] args) { ArrayList list ...

Docker image SpringBoot Jar package Preface Pack Project Making Docker Mirrors View and run Docker images Access Interface Preface Let's start with a general process. I'm building a project with SpringBoot, typing it directly into a Jar package, running on port 8082 on Linux, and changing the na ...

Introduction to using Spring AOP The two core functions of Spring are IOC and AOP.It's convenient when we use Spring's AOP functionality.You just need to configure it below. @Component @Aspect public class MyAspect { //PointCut matching methods must be methods of bean s in Spring //Pointcut s can be defined in the following ways or combined in ...

Java learning_ 08_GUI programming GUI programming 1. Introduction 2. Introduction to AWT 2.1 introduction to AWT 2.2 components and containers 2.3Frame 2.4 Panel 2.4.1FlowLayout 2.4.2 BorderLayout 2.4.3 GridLayout 2.4.4 layout exercise 2.5 event monitoring 2.6 graphics 2.7 mouse event adapter 2.8 ...

A new understanding of the concurrency modificationexception and strange phenomena in Java collection iterating through the source code preface 1, Scene settings 2, Accident site 2.1 code throwing exception ConcurrentModificationException 2.2 no error is reported, but the expected result is not achi ...

catalog Usage scenarios objective Implementation mode Premise: thinking Core class test method Source sharing Usage scenarios Input the scheduled task into the database (the advantage of this is the visualization of the scheduled task, and the execution time of each task can be modified dynamically), and execute the corresponding method ...

                        . 1 overview of properties public class Properties   extends Hashtable<Object,Object>    Properties, from the collection class of JDK 1.0, ...

Java provides rich API s for users to develop quickly and efficiently. This blog will introduce the specific usage of String related classes in common classes, including String, StringBuffer, StringBuilder. catalog: ☑ String class ☑ conversion of String to other types of data ☑ StringBuffer and StringB ...

annotation Annotation is a technology introduced from JDK 5.0 The role of Annotation: It's not the program itself, it can explain the program (it's no different from comment) Can be read by other programs (such as compilers) Annotation format Annotation exists in "@ annotation name&quot ...

The basic concepts of RocketMQ are introduced to you in the previous article. In this section, we will introduce environment construction. The most basic thing in RocketMQ is NameServer. Let's see how it is built first. NameServer RocketMQ requires an environment above JDK8. Let's check the environment first, [root@centOS-1 ~]# java -versio ...