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preface

Cool wind lucky, boundless autumn moon, write face classics, feedback about reading friends. This year, we got offers from Alibaba, Byte, Tencent, Meituan, Pinduoduo and Xiapi. Huawei is still in the pool. Kuaishou is crazy about resume hanging, and netease does not know why.

The problem is some general knowledge point problem basically, still have network communication, system design and so on comprehensive a bit of the problem. But the interview questions can still be shared.

Face the

  1. In King of Glory, when rendering the map, consider how to render the map in order to appear unstuck due to network fluctuations, which causes problems.
  2. What is the nature of thread safety? What is the difference between a callable and a runnable? What happens when a thread terminates abnormally? How much space does a thread take up? Is it register or memory or something?
  3. What is the difference between Java threads and Linux threads, and why are Java threads needed?
  4. How does volatile work? Where does memory reordering happen? Why memory reorder?
  5. What Java have you used and sent packages to?
  6. 1. Briefly describe the use and principles of BIO and NIO.
  7. What is the difference between concurrentHashMap1.8 and previous versions? A concrete implementation of HashMap. The difference between red-black trees and balanced binary trees. Why not use B+ trees?
  8. Java’s overall GC process, garbage collection algorithm, flow, garbage collector, strong references, weak references, virtual references and other concepts. What if I want to set up a memory buffer that the garbage collector does not operate on?
  9. JVM memory partitions. If Java GC takes too long, describe what you can do to troubleshoot the problem. Jamp dump command is heavy, what is the alternative method?
  10. The code implements Minor GC every five minutes, if you want FullGC
  11. What ThreadLocal looks like. Why there are memory leaks and how to avoid them.
  12. What are the types of exceptions in Java? How do you deal with exceptions at ordinary times
  13. Spring’s IOC and AOP and MVC mechanisms, whether singleton beans in Sping can rely on multi-instance beans
  14. What are the benefits of Springboot starting dependencies and why using MyBatis is not applicable to database connection pooling
  15. If tomcat has two projects, how does Tomcat distinguish between the two projects if they have the same class?
  16. This article describes the properties and implementation of ACID in MySQL, what consistency types of ACID, how to implement optimistic lock, describes the isolation mechanism and implementation of MySQL. Introduce the structure and implementation of MySQL index.
  17. If MySQL wants to insert 100,000 pieces of data, what is a better way?
  18. Redis supports several ways to cluster, Redis hop table to quickly find the KTH smallest element how to do.
  19. When a thread in Netty’s thread pool establishes a connection, the connection always belongs to the request, and Netty uses only one socket on the server.
  20. This section describes TCP three-way handshake and four-way wave transfer. What is the MTU at the IP layer and how to detect the MTU between machines.
  21. The difference between processes and threads. How processes communicate. Contents in thread space. Open a file in the process and other threads can read and write the file directly. What is the difference between user mode and kernel mode for reading and writing files?
  22. Why memory is paged, what virtual memory is used for, and whether dirty pages in memory are done by hardware or software.
  23. How to implement 2kQPS with a single thread For the server pressure test, 1s evenly send 2k messages, can be returned asynchronously.
  24. Nginx and Redis can handle many requests at the same time, at ten thousand levels, via a signal-like mechanism of the IO model in Linux. Like this C10K problem, that is, how to deal with 10000 concurrent connections in a single machine.
  25. Design a high concurrency seckill system, where the blocking queue is implemented.
  26. How to implement cookie and session mechanism.
  27. The application of token in distributed server, what framework is used to verify token; How else can you do asynchronous frameworks besides Redis?

conclusion

Whether it is the source code of Spring, Netty and other frameworks, the source code of various middleware, or some practical engineering highlights can be highlighted.

But for the actual project may be more difficult I recommend you to look at the RPC source code, and then look at the Netty source code to see how network communication is done, these two aspects of the feeling will be very closely related to the actual. Or take a look at Spring’s source code, where actual Java engineering is almost a must and a plus.

In order to be more convenient to study, the information is also sorted out for everyone! See the end of the article for more information and video interviews!

Writing is not easy, feel helpful also please three even + attention support, also welcome you to raise questions, thank you!!

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