Alibaba (one side)
Ali found a senior who pushed it internally. To be precise, it should be a direct push. It was the resume he recorded directly for me. The Ali Ant Financial, which he entered undergraduate, is great, right? I really admire it. It is the first time to fill in the information on the official website, think about how famous Jack Ma is, and think about top technology like Ant Financial. I am a little excited and a little looking forward to it.
After recording the resume, wait for the resume evaluation. It turns out that you may not get an interview opportunity to find an interview, and whether you can get an interview opportunity needs to go through a resume evaluation (I just know that it is not so easy to push a written test), after all, an internal push You can avoid direct interviews with online written examinations. The first echelon of the Internet like Baidu, Ali, and Tencent’s written examinations are really difficult. I have done the written examination questions of these companies in the past few years. It is really too difficult. In Ali's school recruitment group, I saw many graduate students researching algorithms, front-ends, and Java research and development. After the resume evaluation, they have refused to get an interview opportunity. I thought, I am a graduate student. Although I have a good foundation in Java, I am also familiar with the three major frameworks. The projects are all designed by myself, and my resume is just a piece of paper. Can I get an interview opportunity?
One week after completing the information, I received an interview call from Alipay. I suddenly became so nervous that I actually got the opportunity to interview.
Self introduction
- Briefly introduce your project
- How do you optimize the performance of a broadcasting system with 500 users
- When the user submits the request, but immediately presses the withdraw button, how do you deal with the performance-related data landing problem?
- The underlying implementation principle of Lucene, its index structure
- The difference between ibatis and hibernate
- How does ibatis realize the mapping and what is its mapping principle
- Java I/O low-level details, pay attention to the low-level details, not how to use
- What do you know about mysql
- Talk about the four characteristics of database transactions, why mysql transactions can guarantee failure rollback
- How many types of mysql database locks are there and how to write locked SQL statements
- Under what circumstances will mysql trigger a table lock
- Page lock, optimistic lock, pessimistic lock
- TCP three-way handshake process
- The difference between process and thread
- Is the operation of redis atomic?
- The underlying implementation principle of ArrayList and LinkedList, usage scenarios
- B+ tree
- An arithmetic problem, in an integer array, there are positive and negative numbers, find the substring with the largest sum
- The idea of dynamic programming
- What do you want to ask
After Ali, he became suspicious of life. There were really many, not many, but the underlying principles were not answered. The next day he checked the status and turned out to be rejected. It turns out that learning can't just learn the surface . As a R&D staff, it is not enough to know how to use it. You should know the underlying principles more. Otherwise, how can you optimize if there is a performance bottleneck? How can you handle tens of millions or even billions of concurrency per second?
There are a lot of low-level questions that have not been answered. **What next? **Learn!
Ctrip (one side)
Ctrip also looked for an introductory interview and interviewed directly.
- Self introduction
- Introduce the project
- Have you done stress testing for your concurrent projects?
- The underlying implementation principle of haspmap, how to solve the conflict problem
- Is haspmap thread safe
- Common methods of object
- What do you want to ask
After Ctrip was eliminated, the problem is actually very simple. I felt very puzzled when I was eliminated at the beginning. I was a little depressed. It was just a little hesitation on the thread safety issue, and the answer was right in the end. But now that I think about it, even if the haspmap is thread-safe, I have to consider it. I am not a qualified Java engineer at all and it is only natural to be eliminated. Suddenly I feel that I am not solid in my studies, and I become a little anxious. There are even problems with the basics of java. What are you doing next? Learn!
After being rejected by Ali and Ctrip for more than a week, I did not receive any interview calls. I took the written test of Meituan and Today’s Toutiao, and they all hung up. In fact, I also learned a lot of Java technology before, but it is still incomplete. Let's continue to make up.
Although it is very low, I still insist on reading every day. To solidify all kinds of Java foundation, think in java and read it again; multithreading, concurrent package; collection class, the bottom layer of each collection class, the bottom source code of haspmap, the bottom source code of concurrentHaspMap, more areas understand why, not how kind;
Look at the virtual machine from memory management to class loading; the art of concurrent programming in java; review servlet/jsp technology; understand the technical points of ibatis and the underlying source code of ibatis; review the key points of each of the operating system database computing networks; understand the technology of MySQL Key points: Spring's core technologies and ideas IOC, AOP, springMVC;
Lucene's index structure, search characteristics, why use it to replace the full-text search of the database; Redis technical points, from five data structures to optimistic locking transactions to data security master-slave replication and persistence...; keep in mind the common commands of the Linux system and Operation; classic design patterns, singleton lazy bad guys, etc.; review data structure balance binary tree B tree B+ tree, review algorithm brush leetcode...Of course, there are many more.
Jingdong (written test + two-sided technology + one-sided hr, get an offer)
one side:
- Self introduction
- Introduce the project
- What are the ways to achieve java multithreading
- CountDownLatch
- Spring's core technology
- Tell everything you know about database transactions
- Chat with the interviewer and talked a lot about the technical problems of login verification (some nervous)
- What do you want to ask
Two sides:
- Self introduction
- Introduce the project
- Tell all you know about the Java concurrent package technology (volatile, lock reentry, LinkedTransferQueue byte addition to improve concurrency technology, ConcurrentHaspMap combined with volatile happen-before read optimization)
- Redis configuration file (AOF&&Snapshot&& master-slave replication)
- WebSocket long connection problem
- Spike business scenario design (transactions, logic adjustments, row-level locks, database concurrency, mybatis calling stored procedures)
- Will you write front-end (Yes, but only know how to write, know how to write jQuery, CSS3)
- What development tools do you usually use? What is the difference between IntelliJ IDEA and Ecplise (shortcut key)
- Chat with the interviewer and discussed a lot of issues about the large amount of concurrency in the background
- What is your future research direction
- What do you want to ask
Jingdong’s questions have been answered, and I feel that the two sides really reflect a person’s R&D skills. Fortunately, I have answered them all. Talking to the interviewer about the back-end concurrency technical issues of their department has benefited a lot. Sohu’s I won’t send it out, and finally successfully got the Jingdong offer from Jingdong.
to sum up
The above is a collection and sharing of interview questions for large-scale Internet companies, and share them with you. I hope everyone can understand what are large-scale Internet companies' interview questions. If you feel that you have gained something, you can click to follow the collection and forward a wave, thank you for your support! !
Finally, in response to the above frequently asked interview questions, I also summarized most of the interview questions and answers involved in the interview for java programmers with more than 1-5 years of development experience. Documents , study notes files and architecture videos are made. The information is shared with everyone for free , hope to help you review before the interview and find a good job, and also save everyone's time to search for information on the Internet to learn.
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