Ali Cainiao International Java R&D experience (three sides + summary): JVM + architecture + MySQL + Redis, etc.

Summary of the key points of the Java interview:

Data structure and algorithm, JVM memory structure, garbage collector, recycling algorithm, GC, concurrent programming related (multithreading, thread pool, etc.), NIO/BIO, performance optimization, design pattern, Spring framework: distributed related: Redis cache, Consistent Hash algorithm, distributed storage, load balancing, etc., microservices and Docker containers, etc.

Alibaba Cainiao International 3 Side Summary (Java R&D)

One side (50 minutes)

1. Let me introduce myself first, briefly introduce what projects I have done before, what technologies I used, etc. I didn't ask the details of the project in detail, but the specific functions and business must be explained clearly.
2. Interspersed with some basic knowledge will be asked. After more than 50 minutes of interviewing, I basically finished all the questions I can ask about the basics of Java.
3. JVM garbage collection, can fullgc reclaim the method area
4. Data types supported by redis to jump table, redis synchronization strategy
5. How to implement lru by yourself
6. The data structure of mysql index, why use B+ tree instead of B tree
7. Transaction isolation level, aggregate lock and non-aggregate lock (asked a very detailed question: how to use repeatable read isolation levels to avoid phantom reads)
8. The constructor parameter of the thread pool, the rejection strategy of the queue
9. Spring related, bean life cycle, circular reference problem how to deal with spring
10. Why concurrentHashmap1.8 gave up the segment lock
11. Database sub-database sub-table related

The sensory side mainly examines the breadth of knowledge

Two sides (30 minutes)

1. The principle of springAOP, how the dynamic proxy is implemented
2. snmp
3. How to troubleshoot and solve the interface response speed when fullgc is very slow
4. netty, how to avoid NIO empty loop, zero copy
5. Asked some simple algorithms, talk about ideas

The two-sided investigation is mainly about the depth of knowledge and the ability to solve problems. The opening routine is to introduce yourself and the project briefly.

Three sides (40 minutes)

1. Why is the role of Kafka replicas better than other message queues.
2. Commenting on the issue of long links and short links on Weibo, let me design a service to handle long links and short links, including how to read and save.
3. Various chat projects, from project architecture design to deployment process.
4. The difference between solr and mongodb, why not use solr for storing data?
5. Talk about the implementation comparison of distributed locks and distributed global unique ID?
6. Familiar with what aspects of distributed architecture design?
7. Introduce performance optimization cases you have practiced, and optimization ideas
8. Among the projects you have participated in, which project has made you the most rewarding, what technologies have been used in this project, and where are the challenges?

The three-sided interviewer pays special attention to the implementation and details of the project. Why are these modules divided, what each module does and why these technologies are used, all need to be explained very clearly. If he has any questions, he will immediately interrupt to ask questions.

The above is the three-sided problem of rookie Java research and development. The following is the latest summary of the scope and answers of the 450 Java required exam questions and answers for Ali P6 senior , including the most complete MySQL, Redis, Java concurrent programming, etc. interview questions and answers, for reference~

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