Remember life for the first time Alibaba denied experiencing technical interview
As an R & D personnel, I believe that we have a giant dream. Dreams of one day, manufacturers can go to work, to enjoy the kind of Gaoshourulin working environment, to really understand what is really high concurrency , mass storage , big data , go to the big stage play to their wisdom, do a service ten million users of the product, promotion and pay rise, to embark on life "peak." Yes, I also have such expectations, look forward to joining such a giant BAT, from one side refused to resume probably went through 15 days, in terms of process, Ali interview experience is good, giving candidates , both in time and space a lot of the right to choose. On the results, it makes me realize that cognitive blind spots and shortcomings of their own existence itself.
The delivery of post information:
- Department: Ali Baba IOT Division
- BASE: Wuxi
- Level: P7
01 resume
As the pace of wage increases, housing prices can not catch up with the pace of Shanghai, Wuxi himself two years ago in the home, along with the growing age, I feel the pressures of life. From the beginning of 2019 has been planning to have the right opportunity, Wuxi back to work, a chance of afternoon 2019 September 29 , out of curiosity, want to learn about career opportunities related to Wuxi Internet, direct appointment by BOSS, see Alibaba in Wuxi there HC, then prepare a resume, sent to the hiring manager. To tell the truth, the whole Internet needs to read Wuxi, my heart is still some loss due to the following:
- Less fewer opportunities, the company has a good product, a large number of technology outsourcing company
- Payroll than Shanghai, a relatively large gap, basically cut
- Upside potential is limited, work in the Internet industry in the city, more prone to ceiling
Those (in the first-tier cities Beijing , Shanghai , Shenzhen ) IT professionals working in the new selection relegated to first and second tier cities, the need for careful, have to be psychologically prepared.
02 schedule a face
No. 12 October 2019 on a business trip back to Shanghai from Nanjing to move the car, received a strange phone, fixed location display , Zhejiang - Hangzhou , the interviewer will first explained what he wanted to introduce sectoral information and job information, Base case. Next, it is to ask, is it possible immediately to a telephone interview, because the people coming and going on the train ( not prepared for an excuse to refuse ), postponed until next Tuesday (15th October 2019). It is recommended that students receive a telephone interview invitation, in the absence of well-prepared, do not rashly promised a phone interview, it is recommended you have two options:
- The refusal reservation telephone interview, said it plans to own no recent change jobs
- Extended interview, that the current busy, will be extended interview fully prepared
According to Ali's friends say, before the recording has rejected, would later interview again, have a greater impact, probably because for the first time before the record was rejected, not directly into the electrical surface areas, even worse, because in the face of HR rejected assessment was rejected by one vote. Words and short, all in all, seriously ready, opportunities are for those who are prepared and ready.
03 interview preparation
Online data collection and collation from the discovery, regardless of the depth or breadth, Ali interview covered all aspects of the problem, if not prepared before, we want to review completed in two days, more difficult, the first major surface is the foundation, the idea is probably review :
- Resume a selection from his most familiar with, there are the technical highlights of the project, combing business processes (What, Why, How) and technology stack (architecture design, middleware, development framework) . Combed these will help in the process of the interview, the interviewer to ask questions and hinted guide, subject to the right of initiative in their own hands, do not be carried away by the interviewer, easy to fall into the pit.
- Algorithms: sorting algorithms (bubble, select, insert, fast row, Hill, merge, heap row, counting the base, barrel row), LRU, search algorithm (Find violence, binary, binary trees, hash), LRU, LFU , FIFO, FILO
- Data structures: arrays, linked lists (unidirectional, bidirectional), trees (binary, a complete binary tree, search trees, red-black trees, multiple trees, B-Tree, B + Tree ), FIG.
- The millennium change JAVA foundation chain gun: the JVM, the Java collections, lock, concurrent programming (CAS, spin, LockSupport), network programming (IO / BIO / NIO), reflective, dynamic proxy, new features, thread pool, ClassLoader, inter-thread communication
- Spring chain gun: the IOC, the AOP, Bean lifecycle Spring, Spring initialization container, Servlet life cycle, the difference between the known processor, and the FactoryBean the BeanFactory, processing of the request Spring, Spring Sons container
- ORM framework: Mybatis principle, a cache, L2 cache, Mapper scanning process, the process of dynamic proxy (JDK comes compared Cglib)
- Database: B + tree index structure classification, indexing, optimistic locking, pessimistic locking, shared lock, exclusive lock, MVCC, GAP, ACID properties, the isolation level, the transaction principle, the cause of database deadlock, how to avoid database deadlocks how to use explain, under what circumstances would lead to failure of the index, how to optimize the database, index, what needs attention
- Middleware: nginx, distribution center (Disconf, Diamond, Apollo), Zookeeper, Elastic-Job, Dubbo, cat monitors, Spring Cloud, ElasticSearch, oss, mq, redis, elk, druid, drools
- Web container: Tomcat, Netty, JBoss
- 协议： Http、Tcp/IP、UDP、Https
- Encryption: the Md5 (salt), AES, SHA1, RSA
- Tools: Maven, the Git, the UML (use case diagrams, flowcharts, the ER, timing diagrams)
- Distributed: CAP, BASE, distributed transactions (two-phase, three-stage, TCC, local news table), mutually exclusive services, power services and so on, distributed lock (mysql, redis, zookeeper), data consistency problem
- Design Mode: combined with the Spring Framework: Singleton, Factory Method, a simple factory, abstract factory, the creator, the chain of responsibility, strategy, agency, template method, observer
- 源代码： JUC、HashMap、ConcurrentHashMap、HashTable、sync、AQS、ReentrantLock、ThreadLocal、Dubbo、Spring、Netty、NIO（epoll、selector）
- Performance Tuning: code, database, cache, NoSql, JVM, static pages, CDN
04 telephone interview
After two days of hastily prepared, very punctual in accordance with the interviewer before the agreed time, appeared at the other end of the phone, while I'm on this.
Simple greeting, reconfirmed Base information, then enter the interview process:
Q1: Please tell us about what you left the most impressive project, which uses technology
Q2: HashMap What is the underlying implementation
Q3: HashMap load factor and the expansion mechanism What
Q4: HashMap since used the red-black tree, then what method should be rewritten
Q5: ThreadLocal is how to achieve
Q6: how to solve the problem of distributed transaction
Q7: how to ensure idempotency MQ messaging and services
Q8: bottom of Dubbo communication Theory and IO model
Q9: Dubbo load balancing algorithm which, by default is what
Q10: Dubbo and Spring Cloud comparison
Q11: is there an open source to find out about Ali's distribution center products
Q12: JDK comes with the thread pool Compare
Q13: Spring AOP principle
Q14: Mybatis course, did not write specific Mapper realization, is the use of what technology
Q15: how Jdk dynamic proxy implementation based
Q16: JDK dynamic proxy and Cglib compare
Q17: database optimistic and pessimistic locking
Q18: Why the database to be indexing, we need to pay attention to what
Q19: have not seen some of the source code, on the next and do
This, the end of the interview, when the entire length of the phone interview 1 hour 10 minutes, relatively smooth, there are several relatively low-level problem, not answer it, can only speak about the lack of global thinking, no, that is not the answer, did not carefully studied the answer is not careful. (These problems alone memory retention)
05 result notice
In an interview after the completion of the first surface, the overall feel pretty good, does have a few problems underlying principle, there is no answer up. The next step is to wait for the results of the interview process, the entire wait for the results of the interview process, the process is probably this:
自信（感觉还可以） ---> 喜悦（还在流程中） ---> 怀疑（未收到二面通知） ---> 焦虑（是不是挂了） ---> 失落（面试被拒） ---> 释然（思考与总结）In the case of do not know the result of the interview, continue to prepare the contents of two faces, recently the company has two more urgent projects are on my side, busy working during the day, at night to review two or three points. Here, thank you very much behind the scenes to support me, to act as logistics department of a small high students. During this period, through internal inquiries friend, four days after the interview, resume status display has been in the process, ha ha ha, I feel there should be a two faces. After about a week later, still have not received a second interview, this time a little sit still. Let a friend inside reconfirmed, painful results. The interviewer to evaluation is: technology deep enough, lack of enthusiasm for technology, human communication and good logic , friends comfort me: an interview just touch, a different interviewer fancy something different , as a RD, his heart most clear (own foundation is not solid), received the results of that moment, my heart is still slightly lost. Lost I own all these years is a reflection and summary. But also to their next work, pointing out the direction. Ali entire interview process ends. ( Tucao about: interview refused, did not receive any mail and SMS notification, it is recommended in the recruitment session, do have beginnings and ends )
06 Reflections and summary
Thinking:
In the interview process, which questions the interviewer left a technical deep enough impression?
About deep enough, personally feel there are several issues of principle, do not answer it, the most deadly.
In the interview process, which questions the interviewer to stay, lack of technical enthusiasm impression?
For technical enthusiasm, not to let the interviewer made a satisfactory answer, existing solutions in the company projects only stay at solving the current problem and can be used on the line stage, the source code is not enough to understand the degree of technical know these stages just to stay in , did not show a technical determination to change the world .
to sum up:
- Usually busy with the team thing, deep curiosity for technology, decreasing
- Curiosity technical principle, gradually lost, just stay at the level of use
- Inadequate preparation, resume after resume screening did not make good use of time, combing knowledge
- In fact, Ali's interview, it is not difficult to imagine, fully prepared in depth and breadth, I believe we can get Offer
plan:
- The opening of this blog, recording growth course
- Start from the foundation, deep source code, understand the principle behind the technology
- Curiosity
- Weekly able to output a technology blog
- This time next year, Ali battles, and strive to enter two faces