Jingdong back-end R&D four sides (with structure interview topic) and B2C mall structure project actual sharing!

The main questions on one side are as follows (mainly focus on the basics, ask very deep and broad questions, and stress interviews):

• First introduce yourself

• Basic problems of data structure algorithms, such as sorting algorithms, binary tree traversal, non-recursive post-order traversal, shortest path problems in graphs

• Algorithm to sort an array by absolute value

• The underlying implementation of hashmap in java

• GC principle of garbage collection mechanism in java, etc.

• Introduce your own project, the data structure data model used in the database, the concept of deadlock (the question should be the deadlock of the database), how to avoid deadlock?

• Optimistic lock and pessimistic lock?

• Consistent hash algorithm

• The association relationship/association method of the business objects in the project, talk about the left outer connection and how to realize the many-to-many relationship model

• Spring IOC and AOP

• How does sping realize (guarantee) transaction consistency and integrity, and the type of transaction propagation mechanism in spring

• Talk about the WEB architecture (it should refer to the j2ee development architecture model), the user scenario usage scenarios in the project

• Knowledge of distributed architecture, such as distributed storage, distributed cache, and distributed computing

• What kind of open source projects do you know about Ali?

• Do you know about Taobao technology?

• Do you know the main business of the Hangzhou Information Platform Division (it is mainly java development, and you can also focus on the workflow engine)

The main problems on the two sides are as follows (mainly the investigation of solutions when encountering problems):

• What are the load balancing algorithms? Understand the diversion of Nginx?

• How to solve high concurrency?

• How does Mybatis use transactions?

• The difference between mysql's myisam and innodb, and why use it like this?

• Handwriting database connection pool

• Asked about the details of redis, distributed cache, middleware, and the usage scenarios of the project.

• Actual working JVM tuning experience, with examples

• Optimistic and pessimistic locking (Java and database)

• How to optimize the amount of large data and the corresponding technical solutions? What do you think of the prioritization?

The three main issues are as follows (focus on the project):

• Have you ever seen a server avalanche in your work? Do you know what circumstances usually cause avalanche scenes?

• Talk about the concurrent programming that you are familiar with. What technologies will be involved and where will the corresponding technologies be applied?

• Talk about the storage methods of distributed sessions, comparisons and differences, which one do you think is better?

• Have you been exposed to distributed global unique ID? What kinds of generation methods are there? Their strengths and weaknesses?

• What does the distributed architecture design include, and what technologies do you use in your work?

• You are leading a technically challenging project. Where are the challenges and how to design and solve them?

• Double 11 spike, the overall design idea?

Generally speaking, it pays more attention to the basics, especially Java's multithreading and concurrency security and database-related. In addition, the specific underlying implementation of the open source framework requires more reading of the source code and summary.

Let me summarize the things to pay attention to in the interview: before the interview, prepare the answers to the interview questions in advance and review the work experience in the resume; during the interview, self-introduction should show your enthusiasm, match with the position, and your own Highlights and interesting places, keep in mind the WWHC and STAR principles, ask the interviewer from the position, department, and enterprise level; keep a stable mind, don't answer the following questions because there is an unclear knowledge point in the technical interview!

Talk about life

The leader, very nice, gave some suggestions. Maybe I think the skills are similar. I didn’t ask much about the skills here, mainly about career development and IBM’s internship content. I think everyone may also have their own ideas. 18 minutes.

hr talk about growth experience: I talked about my understanding of B2B and my own technological growth process.

Here I have summarized some architecture video materials and most of the interview questions and answers involved in the Internet company java programmer interviews. Documents and architecture video materials have also been completed and high-definition java advanced architecture learning mind maps for free sharing For everyone (including Dubbo, Redis, Netty, zookeeper, Spring cloud, distributed, high concurrency and other architecture technical materials), I hope to help you review before the interview and find a good job, and save everyone searching for information on the Internet Time to learn.
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B2B e-commerce mall actual combat experience

The purpose of the e-commerce project is to apply the knowledge of distribution, microservices, performance tuning, etc., and only in the project can you consolidate your knowledge and improve yourself. Practicing e-commerce projects will use cloud servers to build a real development and deployment environment, allowing you to go from zero to actual project combat. When you have the knowledge and architecture design required to familiarize and comprehensively use B2B e-commerce malls, it will let you Confidence increased during the interview, and all the content and architecture knowledge of a mall project are also shared here!

system design

1. Architecture design
2. Database Design
3. Deployment design
4. Basic development framework

User Management Subsystem

1. User registration and login (QR code technology)
2. Authority control (shiro)
3. Single sign-on (session unified cache, sso)

Commodity management subsystem

1. Commodity management (mongodb)
2. Commodity classification (mongodb)
3. Commodity distribution (nosql and mysql data synchronization)
4. Top seller ranking (redis)

Search subsystem

1. Full-text search based on ElasticSearch
2. Search demand analysis
3. Search strategy
4. Index settings
5. Word segmentation algorithm
6. Hit rate optimization
7. Real-time order statistics

Order subsystem

1. Distributed environment generates a unique number (zookeeper)
2. Order business process (message middleware)
3. Order reliability
4. Spike function (redis)
5. Order management
6. Order function (mongodb)

payment system

1. WeChat payment docking
2. Alipay docking
3. UnionPay docking development
4. Distributed scheduling system
5. Statistics
6. data synchronization
7. Task scheduling configuration

backend system

1. Daily management
2. Online IM system (websockedNIO)
3. User behavior analysis (log system design)
4. Report big data query optimization (mysql query optimization)