BATJ high-frequency interview questions: java+microservices+multithreading+distributed+MyBatis+Spring

Foreword:

This article collects and sorts out N common interview questions from major factories. Here are the content you want: Java, MyBatis, ZooKeeper, Dubbo, Elasticsearch, Memcached, Redis, MySQL, Spring, Spring Boot, Spring Cloud, RabbitMQ, Kafka , Linux and other technology stacks, I hope everyone can find a company that suits them and have a happy code.

table of Contents:

Due to the large number of questions and space limitations, not all of the interview questions in the article are accompanied by detailed analysis, but they are compiled into a detailed PDF document that can be shared with everyone. Get free collection at the end of the article

 

Looking at the interview questions can be for the interview, or it can be a way to check and fill in the vacancies of what you have learned, and to understand some core knowledge points more deeply

 

MyBatis interview questions

1. What is Mybatis?
2. Advantages of Mybatis:
3. Disadvantages of Mybatis framework:
4. Applicable occasions of Mybatis framework:
5. What is the difference between MyBatis and Hibernate?
6. What is the difference between #{} and ${}?
7. What should I do when the attribute name in the entity class is different from the field name in the table?
8. How to write a fuzzy query like statement?
9. Usually an Xml mapping file will write a Dao interface corresponding to it. Excuse me, how does this Dao interface work?
10. What is it? When the method in Dao interface has different parameters, can the method be overloaded?
11. How does Mybatis perform paging? What is the principle of the paging plugin?
12. How does Mybatis encapsulate the sql execution result as a target object and return it? What are the mapping forms?
13. How to perform bulk insert?
14. How to get the automatically generated (primary) key value?
15. What is the use of Mybatis dynamic sql? How does it work? What are the dynamic SQL?
16. In the Xml mapping file, besides the common select|insert|updae|delete tags, what other tags are there?
17. In the Xml mapping file of Mybatis, can the id be repeated for different Xml mapping files?
18. Why is Mybatis a semi-automatic ORM mapping tool? What is the difference between it and fully automatic?
19. There are several ways to realize one-to-one in MyBatis? How to operate?
20. There are several ways to realize one-to-many in MyBatis, how to operate?
21. Does Mybatis support lazy loading? If so, what is its implementation principle?
22. Mybatis's primary and secondary caches:
23. What is the interface binding of MyBatis? What are the ways to achieve it?
24. What are the requirements when using the mapper interface of MyBatis?
25. Briefly describe the operation principle of Mybatis plug-in and how to write a plug-in.

 

ZooKeeper interview questions

ZooKeeper is an open source distributed coordination service, created by Yahoo, and is an open source implementation of Google Chubby. Distributed applications can implement data publishing/subscription, load balancing, naming services, distributed coordination/notification, cluster management, Master election, configuration maintenance, name services, distributed synchronization, distributed locks, and distributed queues based on ZooKeeper. Features.

• The difference between zookeeper load balancing and nginx load balancing
• Zookeeper Watcher mechanism-data change notification
• Client registration Watcher implementation
• How does zookeeper guarantee the order consistency of transactions?
• Is Zookeeper's watch monitoring notification to the node permanent? Why is it not permanent?
• How to deal with zk node downtime?

 

Dubbo interview questions

Spring Eureka changed from open source to closed source, Consul is on the rise, and Dubbo is starting to update again. There are still many companies in the market that use dubbo and we need to continue to learn.

• Why use Dubbo?
• What communication framework is used by default, are there other options?
• Is the service call blocking?
• What registry is generally used? Are there other options?
• What serialization framework is used by default, and what else do you know?
• What are the layers of Dubbo's overall architecture design?

 

Elasticsearch interview questions

• How much does elasticsearch know, talk about your company's es cluster architecture, index data size, number of shards, and some tuning methods.
• What to do if there is too much data in elasticsearch index, how to tune and deploy
• How elasticsearch implements master election
• When Elasticsearch is deployed, what are the optimization methods for Linux settings
• Describe in detail the process of Elasticsearch updating and deleting documents.
• When Elasticsearch is deployed, what are the optimization methods for Linux settings?

Redis interview questions

With the continuous maturity of application research and development technology, Redis caching technology has become one of the necessary capabilities for background research and development students. In the interview process of many companies, it is essential to examine the mastery of Redis knowledge points.

• What are the benefits of using Redis?
• Is Redis single-process single-threaded?
• What is the persistence mechanism of Redis? Their advantages and disadvantages?
• Redis common abnormal problems and solutions (avalanche, penetration...)
• Redis expired key deletion strategy?
• Why does redis need to put all the data in memory?
• What is the master-slave replication model of Redis cluster?
• How to set the expiration time and permanent validity of Redis key?

 

MySQL interview questions

Nowadays, the Internet industry uses MySQL the most. However, for advanced Web interviewers, especially for job seekers looking for jobs under 30k, many MySQL-related knowledge points will be basically involved. If your relevant knowledge is vague and irrelevant during the interview Basically, most interviewers from better companies are basically not interested in you. After all, a slightly larger project will eventually let you go deep into the database, and most of the final bottlenecks will first appear in the database.

1. L related storage engine.
2. The principle of MySQL index implementation.
3. MySQL database lock.
4. MySQL SQL tuning.
5. MySQL sub-table sub-database global ID.
6. What are the technical characteristics of Mysql?
7. What is Heap table?
8. What is the default port of Mysql server?
9. How to distinguish FLOAT and DOUBLE?
10. Distinguish between CHAR_LENGTH and LENGTH?
11. Please briefly describe the names of the four transaction isolation levels supported by InnoDB in Mysql and the differences between each level?
12. What is the usage of ENUM in Mysql?
13. How to define REGEXP?
14. The difference between CHAR and VARCHAR?
15. Is Mysql query case sensitive?
16. What are the different tables in Mysql?
17. What kind of objects can be created using the CREATE statement?
18. What are common SQL functions?
19. Does MYSQL support transactions?
20. What field type is good for recording currency in mysql
21. What kind of locks are there in Mysql?
22. What are the method commands for MYSQL database server performance analysis?

 

Java concurrent programming interview questions

1. What is the difference between daemon thread and local thread in java?
2. What is context switching in multithreading?
3. What is the thread scheduling algorithm used in Java?
4. What is a thread group, and why is it not recommended in Java?
5. What is the difference between Executor and Executors in Java?
6. Three elements of concurrent programming?
7. What is a thread pool? What are the ways to create it?

 

Spring interview questions

1. Talk about your understanding of spring IOC and DI. What is the difference between them?
2. What is the difference between BeanFactory interface and ApplicationContext interface
3. What are the ways to instantiate Spring configuration beans?
4. Simply talk about the life cycle of spring?
5. Please introduce the life cycle and scope of Bean in the Spring framework
6. What are the ways to inject properties into beans?
7. What is AOP and what is the role of AOP?
8. What are the core classes of Spring, and what are their functions?
9. How to configure the database driver in Spring?
10. Can the applicationContext.xml file in Spring be changed to other file names?
11. How to define hibernate mapping in Spring?
12. How does Spring deal with thread concurrency issues?
13. Why do things spread behavior?
14. Introduce Spring's transaction management
15. Explain a few terms in Spring AOP
16. What are the types of notifications?

Summary of interview answers

Kafka interview questions

• Are there three key differences between Kafka and traditional MQ messaging systems?
• Tell me about the three mechanisms of Kafka's ack?
• Consumer failure, how to solve the livelock problem?
• In the case of Kafka distributed (not stand-alone), how to ensure the sequential consumption of messages?
• How does Kafka not consume duplicate data? For example, deductions, we can't repeat deductions.

Summary of interview answers

After reading the above content, I believe that everyone has a clear goal and direction. The next step is to find learning materials. We have prepared a set of systematic architect learning materials kits for your reference. The method of collection is as follows:

 

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