interviewer
: Handler There is Loop Dead cycle , Why not block the main thread , What is the principle
psychoanalysis
： It's hard to get into the question , But if you ask ,100% I can't answer it . It's hard for developers to notice that the four loops of a main thread don't block the main thread
** Job seekers :** It should be from The message loop mechanism of the main thread And Linux The loop asynchronous waiting function of . The final will be handle Cause memory leaks , A memory leak must be a bonus
Preface
Android Message mechanism mainly refers to Handler Operation mechanism of , For all of you Handler I'm familiar with it , But I really have Handler？ This article mainly through several questions around Handler Develop an in-depth and expanded understanding of .
Standing on the shoulders of giants will see further . If you are interested, you can go to Gityuan Learn more about , It's all dry . And what he wrote was more authoritative , After all, he is also a backbone member of Xiaomi system engineers .
Share some recent interview questions about performance optimization , Let's see what you know about this ？ Can answer up , In the area of performance optimization , You are at least ahead of 80% Classmate .
1、 double 11 Under the scenario of high concurrency and big promotion , Why can we only place orders , You can't get a refund ？
Answer ideas ：（ Service degradation, etc ）
2、 From what angle can Alipay system optimize performance? ？
Answer ideas ：（ cache 、 asynchronous 、 Distributed, etc ）
3、 How to complete fast statistics of tmall's 100 million commodity data ？
Answer ideas ：（Fork/Join Task splitting, etc ）
4、 How to optimize the transfer and withdrawals function of Alipay? ？
Answer ideas ：（ Uniformity 、 High throughput scheme, etc ）
5、 Taobao network jitter , How to avoid repeated orders ？
Answer ideas ：（ Idempotent equivalence ）
Performance optimization is a big area , Optimize application performance , And front end optimization 、 Structure optimization （ Distributed 、 Cache usage, etc ）、 Data storage optimization 、 Code optimization （ Such as design pattern optimization ） etc. .
And double 11 The key technologies of high concurrency include
service degradation 、 cache 、 asynchronous ..... Idempotency
And so on , Technologies commonly used in the Internet BAT No exception .
summary
Finally, for programmers , What to learn 、 There's too much technology , If you want not to be eliminated by the environment, you have to constantly improve yourself ,
It's always us to adapt to the environment , Not the environment to adapt us ！
Here are dozens of sets related to the above technical system diagram
tencent 、 headlines 、 Ali 、 Meituan and other companies 2021 Interview questions for
, Put the technical points into video and PDF（ In fact, it took a lot more energy than expected ）, contain
The context of knowledge + A lot of details
, Due to limited space , Here is a part of it in the form of pictures .
I believe it will bring you a lot of harvest ：
It's easy to be a programmer , To be a good programmer is to keep learning , From junior programmer to senior programmer , From junior architect to senior architect , Or go to management , From technical manager to technical director , Each stage requires different abilities . Set your career direction early , In order to get rid of peers in work and ability improvement .
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