There is a saying in the IT industry: interviews make rockets and work screws are aimed at programmers.
1. Interview to make rockets
Everyone knows that the interview time is very short (compared to other professional interviews), but the interviewer has to understand the interviewer in such a short time, so he will test the interviewer through various questions. "Building Rockets" not only examines your knowledge reserve, but also contains a lot of issues that are not related to IT. One is to see how you are, and the other is to find out whether you can adapt to the needs of this position.
Two, work screw
Many people feel that they have gone through every possible effort to pass the interview comparable to "building a rocket", but you let me screw the screw. It is really overkill, and the skill requirements of a typical job have been severely magnified! In fact, the company selects you through "building rockets" in order to understand you better, to make your job more detailed and more suitable for you. It looks like you are screwing the screws, but in fact you are building rockets, because of that. The screws are on the rocket. This is called "Building rockets for interviews, screwing the screws at work, if the screws are not tightened, the rocket will fall to the ground!"
The hot June is coming without warning, and there must be many people who are already preparing for the autumn move...
Lessons learned, in the past few days, I have sorted out some of the more frequent interview sites in Spring Recruitment Ali, JD.com, and Meituan, and listed the problems I encountered during the interview, researched it, and prepared for the Spring Recruitment.
3. List of problems faced by Alibaba (bottom layer + thread + JVM + network + MySQL)
1. What are the data structures that Java uses more in development?
2. Talk about your understanding of HashMap, the basic realization of the underlying principles, how does HashMap solve the collision problem?
3. Are these data structures thread-safe? If you answer that HashMap is thread-safe, then ask if you have a thread-safe map, and then ask the conurren package.
4. Are you familiar with JVM? Simply talk about the class loading process, what operations are performed inside? I asked about GC and memory management. Have you done any related configuration in tomect?
5. Then I asked about the http protocol, the basic difference between get and post, followed by the tcp/ip protocol, three-way handshake, and window sliding mechanism.
6. Which databases are used in the development? Answer mysql, what are the storage engines? Then I asked me about the usage scenarios of pessimistic locking and optimistic locking, and the principles of distributed cluster implementation.
7. Then I asked me about the working principle of SpringMVC and MyBatis. Have you seen the underlying source code?
4. List of Jingdong Jingdong problems (distributed+MySQL+JVM+microservices)
1. Dubbo timed out and retry? Dubbo timeout setting?
2. How to guarantee the order of request execution?
3. Distributed things and distributed locks? (Do not deduct negative numbers)
4. Distributed session settings?
5. Performing an operation, the first 50 times are successful, the 51st time is failed a All rollback b The first 50 times are submitted and the 51st exception is thrown, how to set up Spring in ab scenarios? (Communication)
6. What are the uses of Zookeeper?
7. JVM memory model?
8. Is the database split vertically and horizontally?
9. How does MyBatis pagination? How to set up the cache? MySQL paging?
10. Are you familiar with IO? The difference with NIO, the difference between blocking and non-blocking?
11. Distributed session consistency?
12. Is the idempotent design of the distributed interface? "No repeated deductions"
5. List of Meituan’s problems (JVM+Thread+Concurrency+MySQL+Redis)
1. What is the ratio of the old and new generations of JVM?
3. What kind of database indexes are there? Why use B+ tree for indexing? What is the difference between a composite index and several individual indexes? Do you understand the query optimization of large tables in the database? Do you understand the MVCC mechanism? What's wrong with the MVCC mechanism? How to solve this problem? Have you done mysql slow statement tuning? Tell me how you do it? (Database serial bombardment)
4. What are the meanings of jstack, jmap, and jutil? How to troubleshoot JVM related issues online?
5. What are the specific meanings of the 5 parameters of the method of constructing the thread pool?
6. What should I do if a thread pool is processing services on a single machine if there is a sudden power failure? (How to deal with requests in the processing and blocking queue)?
7. What are the problems with using unbounded blocking queues?
8. How does the interface handle repeated requests? What is the specific treatment plan?
9. How to solve the key problem of concurrent competition in Redis?
10. Implement load balancing and sequential polling mechanism? (Consider concurrency)
Six, my review road
The following interviews, source code, distributed, microservices, MySQL, network, JVM, threading, concurrency, etc. I want to talk about have their corresponding study notes. No, no (hee hee~), if you don’t want to find it again , Click on the portal to receive it! !
6.1 Real interview questions (one word: brush!!!)
When it comes to brushing questions, I really want to brush up questions all night to prepare for the interview... Among them, I have collected 25 major interviews, which I personally think are very useful (the interview questions are just that), including JavaOOP. , Java collections/generics, IO and NIO in Java, Java reflection, Java serialization, Java annotations, multithreading & concurrency, JVM, Mysql, Redis, Memcached, MongoDB, Spring, Spring Boot, Spring Cloud, RabbitMQ, Dubbo There are more than 1000 real questions on 25 topics such as, MyBatis, ZooKeeper, data structure, algorithm, Elasticsearch, Kafka, microservices, Linux, etc., and I stayed up late to study it twice (really going to become a "god"~haha~).
25 interview topics (more than 1,000)
6.2 Source code
- The first one is my notes on the Spring advanced source code, mainly including the following
The main content is about
Spring advanced source notes
- The second is the MyBatis source code (come to a small MyBatis source code analysis book)
- The last one is the SpringMVC source code...
6.4 Distributed
There are also some distributed collections, let's take a look.
distributed
6.5 Microservices
Microservice
6.6 MySQL
High-frequency knowledge points, tuning notes, learning routes, etc.
6.6 Network
Speaking of the Internet, I have to take a look at this " HTTP Authoritative Guide (page 716) ", which contains the following six parts and 21 chapters.
The definitive guide to HTTP
6.7 JVM
Tuning knowledge, route outlines, and sorting out knowledge points.
JVM
6.8 Thread
Take a look at "Java Multithreaded Programming Core Technology PDF_322 pages"
Java multi-threaded programming core technology PDF_322 pages
6.9 Concurrency
Learning roadmap
Concurrent
Too much, so close
In fact, I want to talk about an algorithm (very important, very important), but basically this LeetCode, it seems that everyone has brushed it almost, so I won't talk about it here..
There are many like Redis, kafka, data structures, etc. and the like , are not introduced, in fact, this one early in the interview, said the first big interview on the topic 25 all have the. I have been working on all the interviews + study notes mentioned above for more than three months. It is really not easy to collect and organize , and there are many summaries of my own knowledge . It is because it is very troublesome, so I am interested in the above study and review materials. Friends who have not collected, you can directly come to me and share it with you, just click the portal ! !
Make no mistake, say the important thing again,