Preface: About time ago (probably in late May) 3 + 1 interview, always wanted to be a summary, but back a flood of experiments, tests, do curriculum design, have now put this thing done.
3 + 1 interview summary
3 + 1, is a joint enterprise with school personnel to foster a program, for students in junior. This time, our professional computer and network engineering a total of about 500 people, and internship positions only 80, still a little competition. After all, college requirement can not go out looking for their own practice, only here to grab or remain in school. I say what I do not want to stay in a senior school.
Clearly recalled the afternoon of May 19, I took my resume ready, more than 30 minutes in advance to Academy Building, enterprises also continued to the setting up their own "camp", I started looking for my interest business, and they began to talk, and something about the internship.
The first reason is caused by "camp" where things sit two young chiefs, I sat on a chair, and handed them to resume, they asked me some questions, Java to learn how well? You have not done the project? There are other chat, they say they are both big Buddha brothers, then what the work environment is very good, the company is also very convenient traffic near the Temple, and then a day's work time is relatively small, low pressure .. ....
Knowing other companies, to the ant-meter science and technology, he looked at my resume, resume content on chatted, and later he asked about technical problems ...
He said: "I see you have a learning framework, Spring can say about the core of it?"
I replied: "The core Spring, ah, I think that there are three parts, one is the IOC / DI, one AOP, there is the Spring's transaction control."
Then it is to explain to him how these concepts and ideas, which I talked about the benefits of Spring, referred to the decoupling. Then the interviewer will continue to ask me what is decoupled, why need decoupling. I did not really can explain this concept, now recalled this to say ......
I said: "The contact module is coupled with the module, depending on how closely it, decoupling is to reduce this level."
He went on to ask: "Why need to decouple"
I replied: "Because we should try to meet the high cohesion and low coupling within ah"
He was asked: "In principle why you want to do."
I (can not stand a little) answer: "Because the book says so."
Oh excluded cool, I only know what is decoupling, decoupling does not know why, my answer to this question unclear. Looking a bit for their own reasons: usually not very concerned about this to write some concept, only to find the book says so and so did not need to think about why. This is not good, you have to change.
Later, I find the relevant information.
Coupled with lingering literally meaning, "coupled" the word refers to the Chinese language in China is two people together arable land, They each each independently of each other, which is the origin of the "coupling". Coupling is so low as to make the relationship between modules or between each or between each class and then each method is reduced, so as to make each independently, a wrong place, does not affect all , can increase code reusability. That's staggering need for decoupling.
In this way, several companies voted that day. After there will be a lot written examination, re-examination ......
The next focus of talk about gold Fu interview, the first round is the written test, six topics. But at this moment I can only think of one of the three topics.
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Traversal map collection
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By Map.keySet () traversal key and value
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Traversal key and value by using iterator Map.entrySet
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By traversing key and value Map.entrySet
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By Map.values () loops through all the value, but can not traverse key
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The reason for garbled
When you save the file encoding format is only used when encoding format when you save and read using the same encoding format to read the file correctly; for example, UTF-8 encoding, GBK encoding can read Chinese, so if using UTF-8 encoding to save the file, but the use of GBK encoding to read the file will cause garbled, so UTF-8 encoded file should be saved using the UTF-8 code reading.
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Object-oriented features
Package: The attributes and method of the same abstract object class into a hidden object properties and methods implemented and provide external interface through interface to access classes.
Inheritance: abstract characteristics similar to the same kind of things. When inherited, the subclass has the properties and methods of the parent class, and can have their own unique properties and methods, in addition, a subclass can in their own way to implement the functions of the parent class (rewrite).
Polymorphic: Abstract of the same kind of behavior of different kinds of things.
The second round is a technical interview (although only a few problems, but to talk quite a long time):
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Describe what is the class?
I said: "class is an abstraction of a thing, this thing has its own behavior and attributes such as a person, everyone is a class, everyone has a pair of eyes, a nose, is the property of this class, people. can run, you can eat, this is the kind of behavior action. conversion to the code, the property is the data class, class behavior is able to provide the services, methods. "
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Briefly you do this project?
A dynamic blog system ...
(At that time talked about the development process, the use of the technology stack, and so on, and then talk to Ali greater than SMS, the interviewer happens to also have used)
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Ali greater than about SMS verification code function? For this function, if want to change as Tencent, Baidu how to do? Ali will be more expensive because of the attention might want to change where there is a lot of place. (The interviewer said that some time ago he also has this feature is used, it will be more interested in)
I said: "ah so, can you see the code block SMS verification concerning extraction, the interfaces provided by Ali replaced by Tencent, Baidu sex is not, or is the SMS verification functionality is packaged as an interface or an abstract class with different versions to achieve it, should be able to deal with the problem of multiple use. I have not tried, these are just preliminary thoughts, I wondered not feasible, or you can try using AOP? "
At that time I only saw him answering a slight nod, I do not know whether the correct answers, we do not know, we do not dare to ask ah.
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After the internship, if you are willing to stay in the Golden assigned it?
Possible.
After some time, I received a re-examination of notice Fu, let me go to his company, I passed, twenty minutes early, waited in their company. With the little sister of the Ministry of Personnel informed that during this interview is technical, there are two waves, first to the two chiefs Development Department, and later the R & D department is the big brother, they asked questions I have done to sum up:
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Three paradigms database.
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The first paradigm: ensure atomicity of each column (column emphasis is atomic, i.e., the column can not be subdivided into several other columns).
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The second paradigm: the need to ensure that the database table and each column primary key related, not related only to a certain part of the primary key (primary key for the main terms).
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Third Pattern: to ensure that each column and is directly related to the primary key column, rather than indirectly (additional non-primary key column must be directly dependent on the primary key, can not rely on the presence of transfer).
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If you are soon on the plane, and suddenly you have a very urgent task colleagues want you to do right away, how can you do?
I said: "Ummm what can be called superiors, because he did not have time to do this task, let superiors have time to complete the change in personnel on the operating system that the implementation of a process with their own thing, they should tell the CPU, myself. not empty, then let the other idle CPU scheduling process "
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What are you familiar with design patterns? Talk about factory pattern?
Familiar design pattern proxy pattern, plant pattern, singleton, observer mode.
Factory model can be roughly divided into three categories, simple factory pattern, factory method pattern, abstract factory model. The benefits of using the plant model is to facilitate decoupling, can reduce the coupling module and the module.
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If you want to implement an arithmetic calculator, how would you do?
"If you want good design, I think we can use the interface and implementation class to design an interface to define, write four abstract methods, then use the class to achieve it. Or directly use the class without the interface, but I seen before in a book with the idea of interface design would be better. "
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What is the vision for the future of the technology life?
"I think Well, Java ecosystem is still very very prosperous, over time will begin to learn SpringBoot and SpringCloud, there are many frameworks to learn, because it is standing on the shoulders of giants, with the others made good 'wheels', hope that their future may be more research into the source code, to learn some algorithm, you can own repairer wheels, within the next 10 years to become an architect. "
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Talk about your project development process.
"Uh ... first of all to a good database design, and then build a development environment, using the Maven project management, configured profiles, write entity classes, and mainly from the controller to complete the background layer, service layer, dao layer, using json interactive data, front-end will be used js, ajax. "
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Talk about three kinds of difference list.
"Java collection of commonly used list, there are ArrayList, LinkedList, Vector. ArrayList and the Vector which are based on an array of implementation in which the two difference is that Vector relatively old, there are probably at the 1.0 JDK, is thread safe and in the expansion of capacity is multiplied by 2, and ArrayList appear in the 1.2 JDK, non-thread-safe, in the expansion of capacity multiplied by 1.5, which is the main difference between the two .LinkedList is based on a doubly linked list to achieve, in when insertion / deletion, the time complexity is O (1), because the chain can be broken, but at the time of retrieval, the time complexity is O (n), and ArrayList during insertion / deletion, the time complexity is O (n), when the search, but the time complexity is O (1), because the data structures related with it. "
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A detailed description of what is polymorphic, the same method name, return type considered different polymorphic do?
Polymorphism refers to a subclass of objects can be used like the parent class object, the same message can be sent to the parent object, the child may be sent to an object class.
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Talk about Maven.
"Maven is a project management tool, currently used for the management of the project depends jar package, the introduction of the corresponding jar coordinates pom files, automatically downloading dependencies from Maven central repository. Very convenient, and Gradle similar."
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How front and back interact, what data, how to deal with the back-end
"Send http request to the front end of the background, the background get request parameters, return to the front end after processing the data using a json, I usually use a rear end @ResponseBody annotations, the return value is automatically converted to json data."
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Garbage problem
(Written and where the same ......)
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I do have a blog address on your resume, you usually have to learn to make records?
"Mmm record, because I used to think learned not to take notes, then over time it will feel: Hey, what school some time ago, how did the impression that point, the brain is the feeling empty, then feel the need to learn the edge side edge summary record for future review, to facilitate back the state at that time to learn about this point, but having said that did have to make a hard copy of the notes, now is the electronic version of the summary display will be much better. "
Code word for a long time friends, there are a lot did not finish, feeling a little, then TB ...... (The next two companies will not elaborate Kazakhstan)
The second company in Guangdong Groupmark limited technology company, any teacher Haha, written by the first round (examination techniques) into the second round of interviews (technology did not ask, just chat), then actually hung up. . .
Later I reflect on it, I suppose I should not ask was asked a question on the second round of interviews: "If I went to your company, what can I learn?." When I ask them to think a little not quite right, there is a face on the black interviewer, she said:. "You want to learn here are"
Emm ... then four interviewers interview a student, to be honest I was a little nervous, asking inappropriate questions, there is no lower profile, there is no state of mind to put away. (The end result is not passed)
The third company is Guangdong arguments caused Ltd, near the Temple. A written test of knowledge of some of the Java basic questions and some of the front-end, when the two technical interviews, ask questions Hibernate has a number of problems and do their own projects, three are interviewing and talking to veterans, but also two the older female executives, have talked to the company in addition to her son, are, there is a great proportion of men are part of a large Buddha, she chatted about her values, in short, still very happy to talk during. (Final result was the adoption of)
Summarize it, I found myself interviewing experienced much, in fact, felt nothing, it will will not will not, go back to school immediately. But also to focus on grasping the projects he has done, to withstand interrogation interviewer, conversation be confident, and more and more summary records can become a "face tyrants" was.