Advantage for many no qualifications, interview companies is very difficult, this for me, too, from 2, thought is three point one line of life through life, until life changes, just let me have the new ideas and goals, so I this 2 Tony also struggle to get up, unexpectedly won the ali P6. Today, I share this experience mainly in the hope that it can inspire technical people who are also troubled by academic qualifications and have a reference value for their career and technical planning. Thank you!

 

A, interview ali P6 difficult where? (Interview difficult points)

(1) Difficulty lies in “mentality”

The first hurdle to overcome is actually your own state of mind. Because I was born in the second Ben, the base is relatively low, so the interview with Ali Ben is not very confident, let alone senior development post, so it is easier to have no foundation in mind. Therefore, before preparing for the interview, it took a long time to adjust the attitude of the matter, so it is difficult to “attitude” is not right, the attitude is not adjusted, the interview is almost impossible.

(2) The difficulty lies in “requirements”

The second is the requirement, the so-called requirement is actually the job requirements of Ali, that is, as a developer, how much technology stack do you master?

First of all, you have to have something on your resume, and second of all, you have to have something bright, which means you have a deep knowledge of a particular technology, so that it’s refreshing to the interviewer.

So, interview ali P6 post, need to master how much?

  • Java collection: HashMap and ConcurrentHashMap, usually best have read some source code, best know why each parameter is set to so large? What are the benefits?
  • JUC packages must be learned, even if the usual programming is not necessary, but also must be able to. Unsafe, volatile, sync, and other common lock-deadlocks and thread pool parameters. You also need to understand spin, blocking, deadlock, oom, CPU overload, and other basic operations. But that doesn’t mean you can’t do things like top, JPS, JStack, jmap. As well as possible derivative JMM models and MESI protocols.
  • JVM: garbage collection algorithm, garbage collector, JVM memory model, usage of each region, various OOM types, JVM tuning experience, class loading process, parent delegation, etc.
  • Spring has to take the time to look at the source code, usually asking about the bean life cycle, how to solve cycle dependencies, implementation of transaction principles, dynamic proxy principles, etc.
  • Dubbo also has to ask, design framework, load balancing.
  • What are the types of single-threaded models, AOF, RDB, rewrite, master-slave, cluster? Contains some common cache problems breakdown, penetration, avalanche, data consistency, and so on.
  • Mysql, transactions, locks, indexes, B + trees, master slave these are the things you need to know
  • Mq, I use RocketMQ, you have to know why use, repeated consumption, sequential messages, transaction messages, high availability, message loss, squeeze scenario, the whole process of message sending consumption, read the source code better, better blow
  • What about Netty, zero copy, BIO, NIO, AIO, architecture design? Used to see better
  • Algorithm, it is suggested that to brush, my luck is good, simple arithmetic, let I met some fast row, heap row, binary tree, list the reversal of cyclization, link points, jump the stairs and other conventional simple algorithm suggested brush, double needle, dp, recursive these still look for the feeling, big data limited memory scene, have time to try some middle may, Handwritten red black tree if you can, then I estimate the algorithm you steady.
  • Network, HTTP, TCP, HTTPS, UDP, layer 7 network protocol, etc., the best combination of their own understanding, back, you have to recite down.
  • There are also some distributed transaction implementation, architecture implementation, such as grabbing red envelopes, high concurrent orders and other conventional scene design, you design, how do you design? Find some big guns or check online to help you see what bugs there are and what solutions there are? What are the best middleware in the industry?

Technology stack mind map

Two, Ali interview questions (a total of 5)

Ali side:

  • Self-introduction, projects and technical areas
  • Talk about sync’s underlying implementation, lock optimization, versus Lock
  • Take a look at the details of JVM parameter tuning
  • Why? What are the benefits? Describe gc scenarios, how to analyze GC logs?
  • Redis data structure, usage scenarios, micro-blog scenarios how to design user relationships using Redis?
  • Thread pool parameter setting, why this setting, function? Seven parameters
  • How are Spring’s loop dependencies resolved? Why level 3 caching?
  • What is the underlying principle of priority queues?

Second face of Ali:

  • Let me introduce myself
  • Chat program
  • Combine your project to ask you how to design, put forward loopholes, how do you solve? How to improve, in case of failure? Is there a problem with adding a machine? What if I have to get it right?
  • How to design high concurrent single order inventory scenario
  • RocketMQ architecture design principles
  • Dubbo framework implementation principle
  • What have you read recently? How do you study?
  • Can you tell me how to use load balancing?

Three aspects of Ali:

  • This aspect mainly asks about the project, which gives you a strong sense of pressure
  • Combined with the project to ask, why so design? Let you optimize, how do you optimize, guide you to optimize in a reasonable and better way, database design and so on
  • What did you do in the company, what did the various systems line of business do, your performance, handwriting algorithm list inversion?

Ali four sides:

  • What are the main components of the JVM and what does it do?
  • What does the JVM runtime data area contain?
  • JVM garbage collection mechanism, when to trigger MinorGC, etc
  • JVM garbage collection algorithm:
  • JVM tuning tools?
  • Common JVM tuning parameters?
  • Stack difference?
  • What about the CMS garbage collector?
  • How do I determine whether an object can be reclaimed?
  • What are the new generation garbage collector and old generation garbage collector? What’s the difference?
  • Java class loading process?
  • Tell me everything you know about middleware (momentarily confused)

HR:

  • Why ali?
  • You never thought about Ali before?
  • What do you think has changed the most about yourself since graduation?
  • Sum up yourself in one sentence

Note: due to the limited space of the article, the detailed version of the answers to the interview questions are arranged in the document. Please pay attention to the public number at the end of the article to get the PDF

 

Iii. What did I do before I got the offer of P6 post in Ali?

(1) Prepare your resume

Resume’s appearance, but also a key, can you get that big interview, is about to see how your resume, regardless of degree, big value most resume if there is a bright spot, so we on your resume should have prepared, for their outstanding points, including the window on technology, individual character, to practice expression, avoid temporary organization language.

 

(2) Improve skills

As a matter of fact, I have a friend of Ali who told me a long time ago that many people think dACHang values academic qualifications, but the actual situation is not completely that in Ali, heroes are only judged by their ability. Therefore, in daily life, through continuous learning, improve their ability, and strive to pull themselves into the distance between the target value, this is very necessary, but also the inevitable trend in the future.

What I did to improve my skills:

  • ① Read actual combat documents

 

  • ② Read some source code

 

  • ③ Read some technical notes

 

(3) Swipe the interview questions

For base is not very good people, brush the interview question is, in fact, the way of “first aid” effect, so before the interview, ali, I brush is a lot of interview questions, the purpose is not to hope the interview was asked about the original topic, but there is a corresponding understanding for the interview, clear ali interviewer will ask some what, which involves technology stack, etc.

I have something to say about brushing:

  • ①Java core interview knowledge arrangement

 

  • ② Algorithm part (LeetCode+ Algorithm fun)

 

  • ③BAT factory interview question + topic training

 

Make a summary

A lot of academic record is not quite good person, may not have too big confidence to oneself, in fact, anything has “miracle” happening, and this “miracle” key or want to rely on oneself to create. No matter you are white rookie, or technology, daily can not fall behind learning this matter, once behind, it is easy to be eliminated.

Above my experience hope to be able to bring help to you, in addition to their own information on the arrangement can be free to share, need these information friends, help forward + comment on my article, pay attention to the following public number can be free of charge ~