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Original:   RocketMQ message query IndexFile (IV) - red hair - personal space - OSCHINA - Chinese open source technology exchange community First, let's look at the process of indexfile, and then analyze and debug the source code step by step. In addition to providing the messages stored in MessageStore to consumer s through ConsumeQueue, ...

1, Jingdong interview questions 1. Implementation principle of @ Autowired 1. Injection method:         1. Constructor based dependency injection public class UserServiceImpl implents UserService{ private UserDao userDao; @Autowire public UserServiceImpl(UserDao userDao){ this.userDao = ...

Singleton mode 02: lazy mode Text start@Assassin 1. Review the hungry Han model: Briefly review the hungry man mode in a single case mode~ I'm hungry man mode! The so-called hungry man mode means that as long as the class is loaded, the object gf will be created. Even if GF is not used, it will be created. This is the loading mechanism ...

@[toc]Last week, brother song reprinted an article on batch data insertion. He talked with you about how to do batch data insertion quickly.After reading the article, a little partner put forward different opinions:Brother song had a serious chat with BUG and basically understood the meaning of this little partner, so I also wrote a test case a ...

#Unified identity management platform IAM Many enterprises have multiple office systems. Accounts, passwords, roles and permissions need to be set separately and cannot be managed uniformly. I think the unified identity authentication management system IAM has the following three advantages: Establish a unified user management, identity rati ...

This article is excerpted from the Flyweight Pattern of "design patterns should be learned in this way"1 story backgroundBecause a programmer changed a method parameter in the production environment and changed the int type to Integer type, because money was involved, the company suffered heavy losses and the programmer was dismissed. ...

1, String (1) Representation of string java.lang.String represents an immutable character sequence. String is used to represent a sequence composed of characters. It is the most commonly used reference data type. Another string is an array of character (Char) types. (2) String creation • standards: Declare before use • creation ...

Original text: Introduction and principle of CGLIB (through inherited dynamic proxy)   1, What is CGLIB? CGLIB is a powerful and high-performance code generation package. It provides a proxy for classes that do not implement interfaces, and provides a good supplement to the dynamic proxy of JDK. You can usually use Java's dynamic proxy to cr ...

What is SPI technology The full name of SPI is Service Provider Interface, which means Service Provider Interface. If we don't write framework code or develop plug-ins, we may not be so familiar with SPI mechanism, but if we read such as Dubbo and JDBC database Driver package, Spring and the recently popular Spring Boot related starter compo ...

This article is excerpted from the Flyweight Pattern of "design patterns should be learned in this way" 1 story background Because a programmer changed a method parameter in the production environment and changed the int type to Integer type, because money was involved, the company suffered heavy losses and the programmer was dism ...