Programmer Think

Preface Concurrency is an unavoidable topic in Java development.Modern processors are multi-core, and multi-threaded programming is essential for better drying machine performance, so thread security is a required course for every Java Engineer. There are two general ways to address thread security issues: Synchronization: Use the Synchronized ...

In the previous section, when explaining the RegistryDirectory, the dubbo administrator can modify the parameters of dubbo service provider online through the dubbo admin management system, and finally store them in the configurators catalog of the registry, and then notify the RegistryDirectory to update the relevant attributes in the URL of t ...

No matter when you start, it's important not to stop after you start Three SqlSession s DefaultSqlSession and SqlSessionManager and SqlSessionTemplate are three common sqlsesion s I have From the class diagram, you can see that all three of them have implemented SqlSession, that is, they can all represent a session.Unlike others, SqlSessionM ...

1. Preface Sometimes we need to declare some custom servlet filters in the Spring Boot Servlet Web application to handle some logic. For example, simple permission system, request header filtering, XSS attack prevention, etc. This article explains how to declare custom servlet filters in Spring Boot applications and define their respective sco ...

📦 this article and sample source code have been filed in javacore 1, Introduction to atomic variable class Why atomic variable classes are needed To ensure thread safety is an important problem to be solved in Java Concurrent Programming. Java ensures the consistency of multithreaded data by three features: atomicity, visibility and orderlin ...

outline This article continues with the previous one, focusing on customizing mapping, custom objects, and the underlying structure of array collection classes. Custom mapping The previous article described the automatic mapping of Elasticsearch. When creating an index, you can specify the mapping information first, or take the music index as a ...

Significance of testing For a specific problem, through analysis and design, people finally write a program in programming language. If it passes the check of language interpreter (compiler) and can run, the next step is to try to make sure that it meets our requirements. This article is about how to confirm whether the program meets the requir ...

spring boot packs all dependent jars into one jar by default when it packs and runs jars. This is inconvenient because the packaged jar packages are relatively large and need to be uploaded to the server for a long time. Here, we can use the assembly plug-in to package dependent jars into external independent folders. In the future, we only nee ...

1. Basic concepts of locks 1.1 CAS and Polling 1.1.1 cas implements locks CAS is increasingly used in lock implementations to acquire locks by exchanging values for a given variable using the processor's CAS instructions 1.1.2 Polling Lock Thread CAS failures are most likely in multithreaded concurrent scenarios, and a polling attempt to retr ...

1, Retry scenario The remote call encounters current restriction or timeout, but the idempotent of the request needs to be considered in the case of concurrency, which is not the problem to be discussed here 1. When to retry -- when there is an exception or Success is false Retry policy: exception verification and result verification 2. Whe ...