Alibaba (one side)
Ali found a friend to tweet internally. To be precise, it should be a direct tweet. It was the resume he directly recorded for me. The Ali Ant Financial Service he entered as an undergraduate is amazing, right? I really admire it. It was the first time to fill in the information on the official website, thinking about how famous Jack Ma is, thinking about the top technology such as Ant Financial, a little excited and a little looking forward to it.
After recording the resume, wait for the resume evaluation. It turns out that if you find an internal referral, you may not get an interview opportunity. Whether you can get an interview opportunity requires a resume evaluation. You can avoid the direct interview of the online written test. The written test of the first echelon of the Internet like Baidu, Ali, and Tencent is really difficult. I have done the written test questions of these companies in the past few years, and it is really difficult. In Ali's school recruitment group, I saw many graduate students research algorithms, front-end, Java research and development. After the resume evaluation, they have been rejected and have not been interviewed. I thought to myself, I am a graduate student, I am self-taught in Java research and development, and the projects are all designed by myself, and my resume is only a piece of paper. Can I get an interview opportunity?
One week after filling out the information, I received an interview call from Alipay, and I suddenly became so nervous that I actually got the opportunity for an interview.
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Self introduction
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Briefly describe your project
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A broadcast system with 500 users, how do you optimize performance
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When the user submits the request, but immediately presses the withdraw button, how do you deal with the performance-related data landing problem?
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The underlying implementation principle of Lucene, its index structure
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The difference between ibatis and hibernate
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How does ibatis implement mapping and what is its mapping principle?
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The underlying details of Java I/O, pay attention to the underlying details, not how to use
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What do you know about mysql
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Let's talk about the four characteristics of database transactions, why mysql transactions can guarantee failure and rollback
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How many locks are there in the MySQL database, and how to write the locked SQL statement
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Under what circumstances will mysql trigger a table lock
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Page lock, optimistic lock, pessimistic lock
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tcp three-way handshake process
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difference between process and thread
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Are redis operations atomic?
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The underlying implementation principle of ArrayList and LinkedList, usage scenarios
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B+ tree
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An algorithm problem, in an integer array, there are positive numbers and negative numbers, find the substring with the largest sum
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The idea of dynamic programming
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What do you want to ask
Ali became suspicious of life after one side, and there are really many, not many, the underlying principles have not been answered. The next day, he checked the status and turned out to be rejected. It turns out that learning cannot only be superficial. As a R&D personnel, it is not enough to only know how to use it. You should know more about the underlying principles. Otherwise, if there is a performance bottleneck, how can you optimize it? How can you handle tens of millions or even hundreds of millions of concurrency per second?
There are many underlying questions that have not been answered, what do you do next? learn!
Ctrip (one side)
Ctrip found an internal referral again and interviewed directly.
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Self introduction
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Introduce the project
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Have you done stress testing on your concurrent project?
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The underlying implementation principle of haspmap, how to solve the conflict problem
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Is haspmap thread safe?
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Common methods of object objects
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What do you want to ask
Ctrip was eliminated after one visit. In fact, the problem is very simple. I felt very puzzled and depressed when I was eliminated. I just hesitated a little about the thread safety issue, and finally got the right answer. But now that I think about it, I have to consider whether the haspmap is thread-safe or not. I am not a qualified Java engineer at all, and it is natural to be eliminated. Suddenly I feel that I have not studied solidly, and I become a little anxious. Even the basics of Java have problems. What do I do next? Learn!
More than a week after I was rejected by Ali and Ctrip, I didn't receive any interview calls. I took the written test of Meituan and Toutiao, and I hung up. Well, keep making up.
Although it is very low, I still insist on reading every day. To solidify various Java foundations, think in java and look again; multithreading, concurrent packages; collection classes, the bottom layer of each collection class, the underlying source code of haspmap, the underlying source code of concurrentHaspMap, and more understanding of why, not how like; look at the virtual machine from memory management to class loading; the art of java concurrent programming; review servlet/jsp technology; understand the technical points of ibatis, the underlying source code of ibatis; review the key points of the operating system database network; understand MySQL The technical points of spring; the core technology and ideas of spring IOC, AOP, springMVC; Lucene's index structure, retrieval characteristics, why it is used to replace the full-text retrieval of the database; Redis technical points, from five data structures to optimistic locking transactions to data Secure master-slave replication and persistence.....; keep in mind the common commands and operations of the Linux system; classic design patterns, singleton lazy villains, etc.; review data structure balanced binary tree B tree B+ tree, review algorithm brush leetcode ..... Of course , and many, many more.
Jingdong (written test + two-sided technology + one-sided hr, get the offer)
one side:
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Self introduction
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Introduce the project
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What are the implementation methods of java multithreading
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CountDownLatch
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Spring's core technology
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Say everything you know about database transactions
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Chatted with the interviewer and said a lot of technical questions about login verification (a little nervous)
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What do you want to ask
Second side:
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Self introduction
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Introduce the project
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Tell all the technologies you know about the concurrent package of java (volatile, lock reentrancy, LinkedTransferQueue byte addition to improve concurrency technology, ConcurrentHaspMap combined with volatile happen-before read optimization)
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Redis configuration file (AOF&&Snapshot&& master-slave replication)
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WebSocket long connection problem
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Second-kill business scenario design (transactions, logic adjustment, row-level locks, database concurrency, mybatis calling stored procedures)
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Will you write the front end (yes, but only, will write jQuery, CSS3)
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What development tools do you usually use? What is IntelliJ IDEA better than Ecplise (shortcut keys)
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Chatted with the interviewer and discussed a lot about the large concurrency in the background
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What is your future research direction?
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What do you want to ask
JD.com has answered all the questions. I feel that the second side in particular really reflects a person's research and development skills. Fortunately, I answered all of them. It was a great benefit to chat with the interviewer about the back-end concurrent technical issues of their department. Sohu's I will not post it, and finally successfully got the Jingdong offer from Jingdong
If you are Java engineering, high performance and distributed, explain the profound things in simple language. Friends of performance tuning, Spring, MyBatis, Netty source code analysis can add my Java advanced group: 675047716, you can exchange and learn with Ali Daniel in the group, and share the video of Java large-scale Internet technology with you for free.
Summarize
The above is to collect and share the interview questions of large-scale Internet famous enterprises, and share them with you. I hope you can understand what are the interview questions of large-scale Internet famous enterprises.
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