The latest 2021 Pinduoduo Java Interview Questions (five-sided live), comprehensively covering Java advanced to high concurrency

On-site Java five-sided questions, with benefits at the end of the article: Alibaba Ant Financial's required exam questions and answers

Pinduoduo Java side

1. Detailed description of HashMap, HashTable and CocurrentHashMap

2. Network IO model? What is multiplexed IO? The difference between select and epoll?

3. The TCP three-way handshake process, what is the problem if there is no third handshake?

4. What are the commonly used thread pools? Their respective application scenarios?

5. Java class loading mechanism? What are the benefits of the parental delegation model?

6. How much do you know about JAVA concurrent package components?

7. When does multi-threading deadlock occur? How to prevent it

8. Operating system's user mode and core mode switching conditions and why they need to be switched

9. Characteristics of database transactions? Transaction isolation level? Transaction realization in the project? Examples of dirty reading, non-repeatable reading, and phantom reading?

Pinduoduo Java Two Sides

1. Database index? B+ tree? Why build an index? What kind of fields need to be indexed, and what are the general considerations when indexing? Will the index make the insert and delete operations inefficient? How to solve it (sub-table operation)?

2. Design pattern, singleton pattern, how to ensure thread safety? The lock efficiency is too low, how to improve the efficiency?

3. CAS? What is the essence of CAS? What is atomicity? Compare and Swap two-step operation, why can guarantee atomicity (involving CPU instructions)?

4. What do you know about the implementation of distributed locks? Which lock do you recommend?

5. What are the persistence operations of Redis?

6. How to use redis to process hot data

Pinduoduo Java three sides

1. What message queue middleware have you contacted? How to choose?

2. Talk about your understanding of SOA and microservices?

3. Talk specifically about Spring Cloud service and registration?

4. Do you understand distributed caps and what do they mean?

5. Network programming nio is related to netty, netty's threading model, zero-copy implementation?

Pinduoduo Java Four Sides

1. Is Redis single-threaded or multi-threaded? How to do Redis distributed cluster?

2. Do you know about cluster avalanches?

3. Talk about the realization of peak shaving and current limiting in high concurrency scenarios?

4. What is personally the most satisfying among the projects you worked on before, talk about your architectural design ideas?

5. What are your plans for the next 2 years?

Pinduoduo Java Five Faces (HR)

1. ​Why leave the last company?

2. Why choose here?

3. How to treat the problem of overtime?

4. How do you usually learn technology, besides Java-related, what other technologies will you learn about?

5. What is the expected salary?

The above is the 5 questions on the site of Pinduoduo, the following 2020 latest Pinduoduo interview answers and Ant Financial's senior Java required exam questions and answers.

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Ant Financial Senior Java Compulsory Exam Questions and Answers

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