My friend recently went to JD.com for an interview. It took about 90 minutes for the three interviews. The questions were very comprehensive and needed to be fully prepared. Except for the concepts, the questions were a bit confusing.I classified those topics and sorted out the answers into redis cache, high concurrency, distributed, microservices, etc. Next, I will share my interview experience with JD.com + some of my study notes.

Note: The redis cache, high concurrency, distributed, microservices, etc. that need to be sorted out by the editor, interview answers, study notes, thinking mind map (xmind) friends can get it for free by private message!

Jingdong's interview questions about redis cache:

How is the cache used in the project?Why use cache?What are the consequences of improper use of the cache?

What is the difference between redis and memcached?What is the threading model of redis?Why can redis single thread support high concurrency?

What data types does redis have?In which scenarios is it more appropriate to use?

What are the expiration policies of redis?What are the memory elimination mechanisms?Write down the LRU code implementation?

How to ensure high concurrency and high availability of redis?Can you introduce the principle of master-slave replication of redis?Can you introduce the sentinel principle of redis?

What are the ways of persistence in redis?What are the advantages and disadvantages of different persistence mechanisms?How is the specific bottom layer of the persistence mechanism implemented?

Can you tell me how the redis cluster mode works?In cluster mode, how is the key of redis addressed?What are the algorithms for distributed addressing?Do you understand the consistent hash algorithm?

Learn what is avalanche, penetration and breakdown in redis?What happens after redis crashes?How should the system handle this situation?How to handle penetration of redis?

How to ensure double-write consistency between cache and database?

What is the concurrency contention problem in redis?how to solve this problem?Do you know the CAS scheme for redis transactions?

How is redis deployed in production?

Analysis of real interview questions

redis cache study notes + xmind mind map

Jingdong's real questions about distributed interviews:

• Tell me how dubbo works?Can the registration center continue to communicate?Tell me about the process of an rpc request?

• What communication protocols does dubbo support?Which serialization protocols are supported?Tell me about the Hessian data structure?Does PB know?Why is PB the most efficient?

• What are the dubbo load balancing strategies and cluster fault tolerance strategies?What about dynamic proxy policies?

• What is Dubbo's spi idea?

• How to perform service governance, service downgrade, failure retry and timeout retry based on dubbo?

• How to design the idempotency of the distributed service interface (for example, it cannot be debited repeatedly)?

• How to ensure the ordering of distributed service interface requests?

• How to design a Dubbo-like RPC framework?

• What are the usage scenarios for zookeeper?

• What are the general ways to implement distributed locks?How to design distributed locks using redis?Is it OK to use zk to design distributed locks?Which of these two distributed lock implementation methods is more efficient?

• Do you understand distributed transactions?How did you solve the distributed transaction problem?Interviewer Psychoanalysis

• How to implement distributed session during cluster deployment?

Distributed study notes+xmind mind map:

Jingdong's interview questions about microservices:

What is Spring Cloud?

What are the advantages of using Spring Cloud?

What does service registration and discovery mean?How is Spring Cloud implemented?

What does load balancing mean?

What is Hystrix?How does it achieve fault tolerance?

What is a Hystrix circuit breaker?do we need it?

What is Netflix Feign?What are its advantages?

What is Spring Cloud Bus?do we need it?

Microservice study notes+xmind mind map:

Summary:

Since I hit a wall on JD.com, I spent a month learning and sorting out these knowledge points, and I am ready to fight again in the future. In addition to high concurrency, distributed, and microservices, I have also sorted out the java foundation.Notes on knowledge points such as microservices, Kafka .And the arrangement of 1500 interview questions of large factories.

If you have any questions during the reading process, please leave a message for discussion. Finally, I wish you all the best of luck in getting your desired offer.