A few days ago, Lao Fan, who had known him for a long time, suddenly received an interview invitation from a large Hangzhou factory. The price was very high- 38k, 16-20 salary .
This made Lao Fan happy. Before the interview, he walked sideways in the circle of friends. After all, if the face was met, his salary would be doubled.
As a result, he died immediately- "I didn't expect that concurrency-related problems are so difficult!"
After stalking, I asked him a few questions. Let’s see how many answers you can answer:
How is the CPU primitive of synchronized volatile implemented?
What is the difference between no lock, bias lock, lightweight lock, and heavyweight lock?
What are the methods for inter-thread communication, inter-machine process communication, and cross-machine inter-process communication?
What is the difference between thread and fiber? Why is fiber relatively lightweight?
Does ThreadLocal have memory leaks? why?
How to use thread pool for the following three businesses:
· High concurrency, short task execution time
· Low concurrency and long task execution time
· High concurrency and long business execution time
After making up for a while, Lao Fan found that these problems were not difficult. It's just that I only have experience in CRUD, and I don't understand multi-threading and high concurrency . Faced with such interview questions, I can only be at a loss.
In fact, it is not just Lao Fan, many people also encounter such problems when interviewing.
If you do the same, it is really necessary to spend 2 hours to participate in a training camp "Multithreading and High Concurrency" taught by Mr. Ma Yingjun .
Time-limited benefits, free learning this time...
Hey , who is the horse soldier?
Graduated from Tsinghua University in 1999, from a programmer to a CTO, he has been committed to promoting Java, big data, and AI to take root in China. Its high-concurrency live courses are very popular, with millions of times playing and learning.
Let the ashes sweeping god Seng Ma soldier teacher take you to systemize the knowledge of multi-threading, help you understand the realization of multi-threading at the CPU level , and how these realizations map layer by layer to those hundreds of millions of users, tens of millions of QPS, Million TPS system.
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Training camp time :
July 22-July 23, 20:00
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(Slap all interviewers who dare to ask high-concurrency questions)
Preview materials:
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The first day of training camp:
The nature of threads (how the operating system and CPU execute threads)
The essence of fiber (why go language fiber is related to thread pool)
What is the nature of concurrency? What is the nature of the lock?
Bytecode primitives for the synchronized keyword
No lock, bias lock, lightweight lock, heavyweight lock upgrade process
Application scenarios of bias lock and heavyweight lock
Start delay of bias lock
Why does the bias lock have a start delay?
The lowest level implementation of spin lock (CAS)
When will spin locks upgrade heavyweight locks
Use JOL to manually observe the process of lock upgrade
The second day of training camp:
What is CPU cache L1 L2 L3?
What is a cache line?
Why are there cache lines?
What is the size of the cache line?
How cache lines affect Java programming
How does the Disruptor framework use cache line filling to improve efficiency?
What is out-of-order execution of the CPU?
How to prove out of order execution of CPU?
What is a memory barrier?
How does JVM use memory barriers to prohibit reordering?
What are the serious consequences of not prohibiting reordering in a DCL singleton?
Understand responsive thread pool applications through an interview question from Ali
Limited time benefits for fans of this account
Scan the code to sign up for "Multithreading and High Concurrency" for free
Limited to 200 places per day
Value-added materials will be sent upon successful registration
Training camp time :
July 22-July 23, 20:00
Limited time benefits, free learning for fans of this account
Full live broadcast, limited time benefits, free this time
Double benefits are waiting for you
Super welfare one
You can choose one of three when you come, and the physical information will be mailed directly to your home~
Super Welfare II· Super Cool Lucky Draw
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Fifth prize: multithreading and high concurrency * 5
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Limited to 200 places per day
Value-added materials will be sent upon successful registration
(The value of the content depends on your actions, never be a collector)
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