Some time ago, I interviewed Ant Financial, ByteDance and Pinduoduo. I won’t go into details when Ant is dead. Ant interviews pay more attention to basics, so the basic skills of Java must be solid. Later, I got the offer of Byte and Pinduoduo, so today I mainly talk about the face of Byte and Pinduoduo.
Pinduoduo
one side
- Chat project
- Explanation of HashMap and TreeMap in Java?
- What is the time complexity of TreeMap query writing?
- How does ConcurrentHashMap achieve thread safety?
- What's wrong with HashMap multithreading? How to deal with it?
- What is the difference between CAS and synchronize? Isn't it possible to use synchronize?
- Does get need to be locked and why?
- What is the role of volatile?
- Give me a piece of paper, draw a nine squares, fill in the numbers, give an MN matrix, and print the MN numbers counterclockwise starting from 1. The time complexity is required to be as low as possible, so let’s talk about the idea first.
- What do you want to ask me?
The questions asked are relatively professional, and they are all relatively common and important technical knowledge.
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Two sides
- Introduce myself
- Do you have any other offers?
- What is the organizational structure of the department?
- What are the modules in the system, what technologies are used in each module, and how does the data flow? I was given a piece of paper, and I briefly drew the flow between systems on it
- How is the link tracking information transmitted?
- How does SpanId guarantee uniqueness?
- In what dimension is RpcContext passed?
- How is Dubbo's remote call implemented?
- How is Spring's singleton implemented?
- Why implement a service governance framework separately?
- Who is leading? Is it still in use internally?
- Have you ever thought about how to make it universal?
- What do you want to ask
HR face
I mainly asked questions about career development, whether there are other offers, and the intention to enter the job. By the way, I also asked about the company's benefits. If you have other offers or experience in large factories, you will get a certain bonus.
Byte beating
one side
- Self introduction
- Chat project
- Are you familiar with Redis and what data structures do you know? How is the bottom layer of zset implemented?
- Do you understand the red-black tree? Time complexity?
- Since the time complexity of the two data structures is O(logN), why does zset not use red-black trees?
- How to determine the number of threads in the thread pool?
- How to determine if it is mainly IO operation?
- How to determine if a computational operation?
- What is the query process of the skip table, and the time complexity of query and insertion?
- Tell me about the principle of Dubbo?
- Does CAS understand? Do you know other synchronization mechanisms?
- Do the problem: Array A, 2*n elements, n odd numbers, n even numbers, design an algorithm so that the odd numbered subscript positions of the array are all odd numbers, and the even numbered subscript positions are all even numbers. Let me talk about your thoughts first
- What do you want to ask me?
Two sides
- Self introduction
- Ask the project
- How is the context of distributed tracing stored and transferred?
- How does SpringMVC login information of different users ensure thread safety?
- Let's talk about mysql, talk about index structure, why use B+ tree?
- How is Dubbo's RpcContext passed? How is the ThreadLocal of the main thread passed to the thread pool? How exactly did the memory leak you mentioned occur?
- Does the thread of the thread pool have to manually remove to reclaim the value? Do you mean the memory leak in the main thread or the thread pool?
- What is index coverage?
- Why does Java design a parent delegation model?
- When do you need a custom class loader?
- Question: Handwriting an object pool
summary
Toutiao’s interview is indeed very professional, and the interviewer finally gave me some advice, that is, when researching technology, we must combine the technical background.
Interviewers have a characteristic, they will grasp a point worthy of in-depth or you did not make it clear and go deep until you make it clear, otherwise the interviewer will feel that you do not really understand.
Free Java architecture learning materials are also provided. The learning technology content includes: Spring, Dubbo, MyBatis, RPC, source code analysis, high concurrency, high performance, distributed, performance optimization, microservice advanced architecture development, etc.
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