Suddenly received the notice of layoffs, the hurried interview was without results, and prepared for the 15th, and successfully won the big factory offer (share my interview experience)

Looking back on my experience during this period of time, in June this year, the company notified the layoffs. I hurriedly went out to meet a few companies, but in the end I did not get an offer. I feel that this year’s winter is a bit cold. I made some preparations for the follow-up interview process, and I can basically go to the HR side. I also successfully got the offer later. I will share my job search experience with you, hoping to give you some reference.

Let me talk about some specific questions I encountered during the interview and interview experience. (Due to space reasons, the answer is not to do all the shows, these questions I have organized into pdf documents free to share with those friends in need, while also finishing find many spent time, a friend in need directly click here is Here, reply to the secret code: CS can receive it for free!!! )

Ali interview questions

1. Multiple threads read and write at the same time, and the number of reader threads is far greater than that of writer threads. How do you think the problem of concurrency should be solved? What kind of lock would you choose to add?
2. Does JAVA's AQS know what it does?
3. Except for the synchronized keyword, how do you ensure thread safety?
4. How would you adjust the parameters of Tomcat itself?
5. Have you ever used Spring's AOP? What is it for? How do you use it?
6. If there are two different implementations for an interface, then how to autowire a specific implementation?
7. If you want to execute your own logic after a certain Bean is generated and assembled, how can you implement it?
8. Why can SpringBoot run HTTP service without putting it in the web container?
9. In SpringBoot, if you want to use a custom configuration file instead of just application.properties, what should you do?
10. If SpringMVC wants to package the output Object (such as XXResult or XXResponse) as JSON output, what should be done?
11. If there is a lot of data inserted into MYSQL, what method would you choose?
12. If the query is slow, what is the first way you will think of? What does the index do?
13. The query is dead, what command do you want to use to find out the query process? What do you usually do after finding it out?
14. How is the separation of reading and writing done? How do you think middleware will operate? What does this operation have to do with transactions?
15. Have you done the sub-database sub-table? What is the online migration process like? How to make sure the data is correct?
16. What do you know or what GC strategy do you use online? What advantages does it have and what scenarios it is suitable for?
17. How many types of JAVA class loaders are included? What is the father-son relationship between them? What does the parental delegation mechanism mean? what is the benefit?
18. How to customize a class loader? Which ones have you used or in what scenarios do you need a custom class loader?
19. What are the parameters for heap memory settings?
20. The difference between HashMap and Hashtable.
21. Implement a HashMap that guarantees the iteration order.
22. Talk about the sorting algorithm, stability, and complexity.
23. Talk about GC.
24. How does the JVM load a class? What are the methods in the parent delegation model?
25. How does TCP guarantee reliable transmission? The three-way handshake process?

Jingdong interview questions

1. What are the commonly used data structures in java? Which ones are thread safe? How to ensure thread safety?
2. Has Lua in Redis been used? What can it be used for? Why can it be used like this?
3. Can you talk about the internal working principle of the thread pool?
4. What does deadlock mean and what are the conditions? What methods can be used to troubleshoot a deadlock.
5. In the transaction process, how to place the user in the repeated payment (cross payment) when paying, please write down the scheme you know or the scheme used.
6. What kinds of database indexes are there, and the difference between them.
7. What does the content displayed on the console include when debugging through the development tool DeBug during program development? What content can help you find and solve problems.
8. In the RPC communication process, suppose that system A provides a method. The input parameter is a JavaBean, and the output parameter is also a JavaBean. The other two system B system and C system call interface. Caller B wants provider A to add a return parameter. Assuming service provider A adds a return parameter, what should the caller of C system do?
9. Understand which design patterns, use pseudo-code to implement a design pattern you are familiar with.
10. Talk about how to use distributed locks.
11. Talk about the principle of HashMap and how HashMap expands the bucket size.
12. What is Redis's pipeline used for?
13. The classification of Mysql index (Btree, hash), what is their use.
14. Talk about the difference between Myisam and Innodb.
15. Know which load balancing algorithms.
16. Talk about the search principle of Btree.
17. Briefly describe the three-way handshake. If the c side initiates a handshake request, what should the s side respond if the connection cannot be established immediately?

Qunar interview questions

1. Self introduction, project introduction.
2. mysql database tuning.
3. sql optimization.
4. Can like use index?
5. Four references to java objects.
6. GC principle.
7. jvm memory structure.
8. Tell me what help and improvement you have learned about jvm in writing code.
9. What would you do for tens of millions of data queries?
10. The difference between HashMap in jdk1.7 and 1.8, why introduce this concept? How to solve hash collision, why 1.8 is better than 1.7, what's the advantage?
11. Regarding your project, if the concurrency is large, how would you transform it?
12. What kind of objects in the method area may be recycled.
13. How do you deal with online cpu soaring 100%?
14. How to deal with frequent FullGC.
15. There are several ways to create thread pools, why the number of fixed-length thread pools is best to be 5, 10, or 15.
16. linux commands.
17. Can the Eden Zone and Survival Zone change dynamically?
18. The difference between redis and memcached.
19. Say a few jdk commands, what does jmap mean.
20. If the concurrency is large, how do you guarantee the correctness of the data?

Are you hungry interview questions

1. The difference between http and https, the principle of https, the difference between http2.0 and 1.0.
2. Java garbage collection mechanism, Java file loading mechanism, tomcat class loading mechanism, lock mechanism, jvm principle and online tuning, jvm memory model.
3. Multithreading, what are the ways to keep processes synchronized, several ways to create threads, and what do you do for i++ multithreaded access.
4. Java design patterns, what are the patterns of singletons, why do lazy people add volotile, volotile memory barriers, and how to avoid deadlocks.
5. Consider the singleton mode of writing, thread safety and low memory consumption (sword refers to the original question of offer).
6. The difference between String, StringBuilder and StringBuffer; can the String class be inherited? why?
7. Handwritten dichotomy sorting algorithm on white paper (the original question on lintcode); the idea of ​​dichotomy search.
8. The algorithm for finding the kth node from the bottom in the singly linked list, handwritten (the original question on lintcode); what are the most common sorting algorithms you have seen, the basic ideas and time complexity of fast sorting.
9. What are the common data structures.
10. Hashmap and hashcode are the same, how to deal with it without equals; hashcode implementation principle, currentHashMap principle, implementation details, how to achieve synchronization; why the class has hascode method, is it mainly in the collection class to implement the hashcode method; how to implement the equals method; Can two different objects have the same hashcode value; what are the common collections?
11. TCP handshake three times and waved four times for agreement.
12. Architecture design is a development problem, design a middleware managed by Nginx, how to design it.
13. All classes inherit from object, what are the direct subclasses of object class you have used, and what are the commonly used methods of object class.
14. Will there be a memory leak in Java, and if so, under which circumstances?
15. The difference between abstract classes and interfaces.
16. How do I expand my professional knowledge level?

Baidu interview questions

1. What is the reflection mechanism of Java.
2. The difference between Cookie and Session.
3. The difference between get and post requests.
4. What are the advantages of IOC.
5. The difference between IO and NIO, the advantages of NIO.
6. What is the difference between JRE, JDK, JVM and JIT.
7. The role of Hashcode.
8. Briefly describe the consistent Hash algorithm.
9. Why do you need to override the hashCode method when you override the equals method? What are the similarities and differences between equals and hashCode.
10. Why does the Map interface not inherit the Collection interface.
11. Tell me a few best practices for using Collections in Java?
12. What is GC? Why should there be GC.
13. When will it cause garbage collection.
14. How many ways are GC? How to configure.
15. When will an object be GC? How to judge whether an object is alive.
16. What is the basic principle of the garbage collector?
17. The difference between Serial and Parallel GC.
18. What is a complete GC process in JVM? How the subject is promoted to the old age.
19. Throughput priority and response priority garbage collector selection.
20. Talk about the main jvm parameters you know.
21. Is there a memory leak problem in Java? Please give an example.
22. What are threads and what are the advantages of multithreading? And briefly talk about several implementations of multithreading.
23. What is the purpose of ThreadLocal, what is the principle, and what should be paid attention to when using it?
24. What is the thread pool? Why use it? How to create a Java thread pool?
25. Can you talk about the usage and advantages of ThreadPool?
26. What is the principle of synchronized? What is the difference between synchronized and ReentrantLock?
27. There are three threads T1, T2, and T3. How to ensure that they are executed in order? How to ensure that T2 is executed after T1 is executed, and what happens if T3 executes a thread in the synchronization block after T2 is executed?
28. What is Optimistic Locking? How to implement optimistic locking? How to avoid ABA problems.
29. What is the difference between livelock and deadlock in Java?
30. What is the Executors class? What is the difference between Executor and Executors?
31. What are Design Patterns? Which design pattern have you used? When is it used?
32. Can you write three singleton pattern implementations?
33. Do you know how Google returns search results to users in one second?
34. How to safely modify the same row of data under high concurrency?
35. How to avoid browser caching.
36. What issues should be considered in the architecture of large websites?
37. Have you been reading any books recently, and what is the most impressive thing?
38. What are the JVM parameters of your online application?
39. Can you briefly explain your understanding of the algorithm?

Interview experience

• The preparation must be sufficient, the knowledge must be as broad as possible, and the depth must be sufficient.
• In the interview arrangement, if you are not in a hurry, try to give yourself as much time as possible, one family for two days, and timely summary and supplements.
• Attitude should be calm. As a technical exchange, the interview depends on part of the luck and some eyeballs. Some interviewers can feel that your interview is over with a mouth. The company you want to go to is not good enough for an interview. Don't get discouraged and continue to prepare.
• In terms of resume delivery, there are many mismatches on the tick, which may be due to my academic qualifications (self-exam), and some of them are a blow to self-confidence. If you feel the same, you may wish to change to BOSS or other platforms. Avoid discouraging self-confidence.
• Writing a resume must reflect your own strengths. It is best to reflect the similarities, what techniques are used, and what problems are solved. What you write on your resume must be well thought out.
• Similar to what your strengths are, what do you think you have done well in your project, and what you can bring to the company, you must first think about this kind of problem, so as not to make it easy to be nervous when playing on the spot.
• The interviews I have experienced are generally at least two rounds of technical skills. If you let you go after a round and you still feel good about yourself, then I think you need to review the interview content and find the relevant content of the question one by one. Most of the problems are that you did not answer the idea. It may be that the depth is not enough, or it may be that the expansion is not enough, continue to refuel.

Answers to interview questions:

Due to space reasons, I will not show the answers here in text. I have compiled these questions into pdf files and shared them for free to those in need. At the same time, it took a lot of time to organize them. (Due to space reasons, the answer is not here. do all the shows, these questions I have organized into pdf documents free to share with those friends in need, while also finishing find many spent time, a friend in need directly click here, right, right, right here, reply signal: CS can be received for free!!! ) Full of sincerity, no routines! ! !

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