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Recently, one of my friends looking for work, have been given a US group, deft companies such Offer, ready to choose one of the entry.
He later received a byte beating phone call informing him to attend the three sides. Distance from the second surface to the three sides of quite a long time, he thought did not play, the results received a notification.
As the Offer has got a lot of manufacturers, he is quite confident about the interview. But after coming back, the performance of particular frustration.
Under a question, turned out to be some of the questions the interviewer asked him not to answer, he said, tugging at source has been the interviewer asked, but he did not look too deep source code, so the answer is not very good.
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He gave me summed up what the interviewer questions about the source part of the main topics are as follows:
1.你看过那些源码吗？
2.那你能讲讲 HashMap的实现原理吗？
3.HashMap什么时候会进行 rehash？
4.结合源码说说 HashMap在高并发场景中为什么会出现死循环？
5.JDK1.8中对 HashMap做了哪些性能优化？
6.HashMap和 HashTable有何不同？
7.HashMap 和 ConcurrentHashMap 的区别？
8.ConcurrentHashMap和LinkedHashMap有什么区别？
9.为什么ConcurrentHashMap中的链表转红黑树的阀值是8？
10.还看过其他的源码吗？Spring的源码有了解吗？
11.SpringBoot的源码呢？知道starter是怎么实现的吗？
The above is my friend by the interviewer blood abuse of process. Full expansion around the source.
So, why the interviewer so like to ask the source? As the interviewer why you need to look at the source of it?
Is it to interview? I do not think so! I think look at the source code has the following benefits:
1) can learn from the source code
For example, we look at the JDK source code, in which there will be a lot of performance optimization, examples of anti-concurrent, there are many places with the design patterns, these are good code that can be used to learn.
For starters, a lot of code format, name, etc. are required to learn the best way to learn is through open source.
2) to understand the principle of in-depth source
Sometimes, we use third-party frameworks, middleware and so on, we want to understand their principle, the most effective way is to look directly at the source. The source code is not a lie.
3) better to solve the problem
As long as people write code that may exist bug, someone else's open source too, can better locate and solve the problem by reading the source code.
4) In order to find a job
Why interviewers like to ask the source, because it can withdraw cash interviewer whether a bookish, is willing to in-depth principle. And companies need is precisely such a person!
How to learn the source of it? There are a few suggestions:
1) start with the overall situation
Do not come on to go directly to the details, start by first aspect of the document, code structure, architecture, stratified and probably understand some of the code of each module are what function. So that when a subsequent in-depth study can just add easy to understand and find the response code.
2) From the problem
Before delving into the study, preferably with a problem, such as learning HashMap source code, you with the problem "when it will be rehash", so you can gradually deepening revolves around their problems. From the point to the surface, and gradually expand.
3) debug-oriented learning
In the source code learning process, it can also debug way to learn, so you can better see the code calls the process of implementation, runtime variables. More aspects to understand.
4) record keeping
Finally, to be diligent record, to their problems and thinking record, behind the side reiterates its review and see.
Well, I hope you have a good habit of reading the source code, I hope you will come across all source categories interview questions can easily get.
Finally, here to share some of the video source and the framework of what the e-book, with video, may be able to reduce the threshold a little early
Part of the video knowledge
E-book
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