[Java plane] Two or three things about the interview.

today finally idle down, so well summed up the experience of the interview these days.
four days of time a total of seven, one is oneself postponed did not go.
Disclaimer: If reproduced please specify the source: http://www.cnblogs.com/wang-meng/p/5895787.html
Because of my previous blog post I found that many are reproduced are no source, direct copy and paste became their product.

Let's summarize the experience of this interview:
1, first understand the market, give their own market positioning
find out about the market for the job you're looking for, so you know what price you can get at one level.
because basically every company will have a good understanding of your expected salary in advance, knowing the market is very helpful for you to find a job.

2, sufficient preparation for the basics
Before the interview I thought the interviewer was more focused on what frame your project used, and how these frameworks worked.
But the real interview is the interviewer is very focused on your understanding of the basic knowledge.
We 'll talk about what we asked in detail later.

3, good job = platform + Payroll
When we choose employing units must be measured from these two aspects, the amount of salary is important, but the platform for our own development is also very important.

4. Keep a good attitude during the interview
our interview process will meet a variety of different styles of interviewers, I from the first interview to the last interview is more or less nervous, some problems I know, but the mind will be blank.
in the interview process we need to adjust their mentality.

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The following is the specific interview process for these days:
I was formally resigned in 2016/9/14, then the Mid-Autumn Festival (15/16/17) finished, in 9/18 days formally began the interview.

September 2016 18 Sunday morning h company
because I vote for my resume is mostly near the home, so I did not go to retrieve the company in the end, this company recruit Java development I delivered the past.
when I ran over the first day, I found out that they were doing it training plus some outsourcing companies.
The first is to accept the resume and then do a written question, here to say the contents of the writing questions:

1, heap, stack, method area difference?
2, how many ways to create a class? Four methods. The specific answer Baidu has.
3. Delete all the files in a folder? Write the code.
4. The concept of serialization and deserialization? Read and write a serialized class. The last to know is to use ObjectOutputStream and ObjectInputStream. Because I do not see much of the IO operation, so this problem directly gave up.
5, two SQL statements, similar to blogs: http://blog.csdn.net/luoxiang183/article/details/52047832 (this blog post is interesting to see)
What is the difference between 6,abstract and native methods?

the above pen question did have five to, that IO operation of oneself did not write, still have 3rd question I just know with recursive return traverse Delete, but specific code write not good.
through this written question revealed some of my shortcomings, I have some blank on the IO, so the pen test did not do a good job, the last word is the interviewer and I chatted about their company's situation, including training, including their projects.
The first interview after their own heart is still very frustrated, a little confidence, but no matter how the road to continue to go on, so then go back to prepare for the next afternoon interview.


September 2016 18 Sunday afternoon R Company
This company is not my own initiative to vote on the resume, this is a plus outsourcing company, HR in the recruitment platform to see my resume active and I contacted, so I went straight in the afternoon.
The first is to do a written test, the written question is their company 17 school strokes of the pen test, are very simple and very basic, finished after the direct arrangement of the interview.
the interviewer is their partner. The first is the technical side, the interviewer is a very nice uncle (about 30 years old), mainly asked me something on the project:
because my last project is to do similar to the e-commerce site, but also the customer outsourcing to us to do, and later I found some learning resources on the Internet myself and for the e-commerce this piece to do a more in-depth understanding, you can see my previous stage of the blog has written. So I have a good understanding of the technology used in this project and how it is implemented.

1, Q: How is your shopping cart module implemented? A: I analyze two situations where the user is not logged in and logged in. There are two things that are not logged in, and how we were thinking about choosing which option to say to him, and then specifically the principle of the shopping cart, which mentions that this place will use Redis.
2, what are the scenarios and benefits of Q:redis use? A: I gave him a detailed account of where we would use Redis in the project, and how Redis would benefit from a traditional relational database, and then how Redis was used in our project, including how to operate Redis.
3, Q: How is the Nginx cluster used in your project built? How does it load-balance? A: I'll start with the question of why to use Nginx, and then tell me what is Nginx reverse proxy, and then how to build Nginx cluster, as well as my responsibilities in the project about this piece.
4, Q: What do you use this Dubbo for? A: About this piece I said first that our project is built by multiple subsystems, and then say that some of the calls in our system need to be used to Dubbo, and finally the difference between Dubbo and WebService is compared.
5, Q: Did the interviewer ask me if I knew some of the classes in the collection? A: I said I saw a bit of HashMap source code, and then talked about the HashMap in the array and the list structure, and how to automatically expand the HashMap, as well as the benefits of expansion (space-time), and then the put/get is how to achieve and so on.
(about HashMap asked a lot of really, suggest you have time to see the source, here is a good summary of the blog: http://blog.csdn.net/luanlouis/article/details/41576373)
6, Q: Memory leak and memory overflow? How do I use tools to debug memory leaks and overflows? A: Because of this I really do not touch much, I just said in what case there will be a memory leak and memory overflow, each case cited an example. about how to debug I'm just saying I know by generating a dump file and then going to debug. The rest is not known.

Asked here the interviewer did not ask me the specific technical problems, and then began to pull up a homely, ask me where the person, which school graduated, and then let me ask him some questions:
First I asked them what the project was, and then asked what frame they were using for what he said, and then asked the project's staffing structure. There were several questions, and at last we had a good chat.
This one side saved, then is two side.

Two side is a more than 10-year project team Daniel, two of the words basically did not ask too many technical questions, basically is to talk about what I did in the last company, and why to resign, as well as some of my values of things, chatted for half an hour after the basically ended, finally personnel came to me began to talk about pay treatment problem.


This is a very easy interview, HR pay is very tempting, but they do the project is not my particular interest, there is also a two-side project director said that their overtime to 11/12 points is common, and is regular. Also because I have a few companies in the back to interview, so I said I next Friday to reply.
(Here's a big point: it's really important to think about your reasons for leaving, and a lot of companies value this, too.)

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September 2016 19 Week L Company
Because I did not know at the beginning that the company is located in the location is not very far, so I took a taxi in the early morning, finally know also very close, because their company is nine points to work, my interview is 9:30, I eight o'clock to the company downstairs, so I waited outside for a good freshman, to nine points I just entered the company interview.
The first is to give me a form, which has your own expected salary, I write down their expected salary, and then they looked after the people said I write the expected salary is a bit high, the rest is to get me a pen test.

The written question is not very difficult, and after it has been done, the interview begins.

1, the life cycle of class loading?
2, how to ArrayList the expansion?
3. What are the advantages of spring transactions?
4, the difference between GetParameter and getattribute?
5, the use of group by?
6, what is the difference between onload () and ready ()?
7, some problems in the project.

Basically I remember so much, as long as I have done some preparation of these interview questions are not problems, interview also talk about the more harmonious, finally personnel found I said I pay a bit high, and said they can accept the highest value, then I just said I need to consider, and then Friday to give them a reply.

September 2016 19 weeks an afternoon B Company
This company is a headhunting to me to find, do car networking aspects of development, this place away from where I live or some distance, so at noon after the interview directly outside to eat a bit of rice went. To the interview of the company found or go a little early, so they hang around the company downstairs, during the discovery of a lot of beautiful girls (haha, a bit far away, oneself is also slowing down their own pressure)

Enter the company first is to do a pen test, here to say the written question:
The pen question includes 30 choice questions and several simple answer questions, the choice question uses the English, and is all multiple choice questions, therefore my pen question does not be good.
Jane's answer is not difficult, the last one on Io operation and write out the code of the problem I did not do.

The rest is the interview, this time is a down two interviewers, it is estimated that one side of the two sides are all up face.
The interview is the first interviewer to ask the question from beginning to end, and then the second interviewer asks the resume from the beginning to the bottom. Finally, they asked again according to their own notes. So the interview lasted a little bit longer. Write a few questions that I don't answer well here .
1, Springmvc How to add filter so as to avoid null pointers? This is the last to know. You can set annotation settings on JavaBean This field cannot be empty.
2, under what circumstances will your project use multithreading? This I did not touch, so I directly say multithreading I have less contact with the project.
3, how can I invoke a private method of a class by reflection? This is the need to setaccessible () method to suppress Java access to the check, at that time felt that the front of the problem was asked the confused, the brain is blank.

The rest is not very clear, the overall interview or asked a lot of questions, most of me can be very good answer up, this is to let me feel the most depressed an interview, but I also contact with such a new interview experience, the overall feel that they are still reaping great.
Finally, the interviewer looked at my expected salary, and said that I wrote a bit high, and then let me go back and so on. I knew I must have been dead, and the next morning I received an email saying that the interview did not pass. I didn't think much, and I was still preparing for the next interview.


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September 2016 20 Tuesday a.m. C Company
This company is a state-owned enterprise, but also headhunting help me to find, early in the morning, sat half an hour of the car to the company.
This company is an independent park, the green is very good, covers a large area, at that time felt that the state-owned enterprises have good money. Finally know that the other office buildings are only their parent company, their research and development department is only one floor of more than 30 people.

After filling out the interview basic information form, the interview is arranged directly, and there is no written examination link.
During the interview, the interviewer asked three questions.
1, what's your understanding of spirng? I said the basic core of spring and then said how our project works with other frameworks.
2, how do you load balance and how are the clusters built? I told him the principle of nginx and how to build it, and the advantages of doing so. Then we talk about how our systems are built and why we use clusters. (In fact, I have answered these questions in several companies above)
3, how do you do this in your shopping cart? (because I wrote the item in my resume that I am responsible for the shopping cart module) and then I told him about the specific implementation and the use of what technology, in fact, these several companies have asked

Ask here he directly to me said he finished, to here my heart is in the drums, I answer can Ah, the interviewer is not satisfied with me? Then he asked me to ask him some questions, and I went on to ask him some specific questions about their project team, feeling that I asked him more questions than he asked me.
This is the HR and the interviewer sit together, and then Hr told me about their company's development prospects, and finally said their salary structure, and then let me go back to the notice.
Similarly, I thought waiting for the notice is out of the way, who knows the next day to call me to say I passed, and then said can give me is the annual salary XX, and their five risk a gold all in accordance with the highest standard to pay, at that time listened to really excited, at that time because has been determined to sign another company, So I thanked the company and refused the offer.

September 2016 20 Tuesday pm L Company

I do not want so blind to look for the interview again, Baidu this company found online scold more, and the company is not very large, so I called the company to say that I can not go, and then expressed their apologies.
after the interview C Company I went home to sleep, feel these days have been running really tired, because temporarily did not find a favorite company, so the pressure is really big, do not want to eat every day, sleep is not good.


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September 2016 21 Wednesday a.m. CQ Company
This company is in my neighborhood, so stepping on the appointment time to the company interview, the company inside the interview more, I was to finish the pen test, and then queued for the interview.

The interview is at 11 o'clock noon, because the back waiting for a lot of people, so the interviewer on the interview for 30 minutes or so, mainly asked me some items on the content, I feel the answer is good, finally to the rice point let me go back to the personnel notice.

finally the personnel call wants me to sign a contract, because in the afternoon the time is to sign another company, therefore this family has also pushed away.


September 2016 21 Wednesday pm M Company
This company is my final choice of company, regardless of platform development and salary requirements are I am very satisfied.
The first is to enter the company, feel the company's environment is very good, because in advance on the internet has a knowledge of the company, but also used their products, so still want to enter the company. I believe we must also use their home products, here I would not be convenient to specifically disclosed.
The first is to start a pen test, pen test is not difficult, after the interview began.

side: Personnel side
here again and I in front of several companies, the first round is the personnel side, asked the question is why resign, asked their own life planning, asked their own values of some things, chatted quite harmonious, followed by two side.

two side: Technical side
The interviewer really made me feel like a Daniel, he didn't look at my resume, but for my work experience to ask me three questions.
1, our server at the start of the moment there are 1000 access, then if you use a hashmap to store it, you will set the initial value of how big?
In fact, I do not have a positive answer to the question of setting the initial value, I told him the principle of hashmap expansion, and said that the HASHMAP threshold is associated with the initial value size and load factor, and then said to weigh the space complexity and time complexity of the situation.
I felt that he was quite satisfied with the answer to the question.

2, we have 700W of the day live, if there is a method parameter is (String citycode) query, how to ensure synchronization?
I said add synchronize or add lock, then he asked me the difference between the two, ask their performance which is good. Then I said in this case we can add lock, then he asked me how to add lock to control the particle size to achieve the best results?
Here I really do not know, because there is not much understanding of the mechanism of lock, but he said it's okay, and then think about how to do, but also prompted me this can quote HashMap design ideas.
The last thing I want to do is to group Citycode, and to locate the location of the Citycode to be queried by the group. For this answer he feels that it can improve some performance, but still not the best.
The last words to tell me the next hash collision, through the hash value to take the mold to get more granular granularity, in fact, here I know HashMap is also through the hash value to locate the position of the array. That's the problem .


3, there are two numbers, a, B, they are 500 digits, how to specify the BigDecimal can not be used to calculate the a+b results? and write the code.
This is the need to write the code on the spot, and he did not give me any hint, need my own thinking.
This problem really let me confused, think for more than 10 minutes, or feel their resilience is not enough, the intention to give up, and finally think of hashmap this thing, haha, feel he good magic.
Thought : (I thought the idea, not necessarily right)

1Map<string,int> A1map =NewHashmap<string,int>();2A1map.put ("A1", 1234567890111111);//Value load less than int type to receive length3Map<string,int> A2map =NewHashmap<string,int>();4A2map.put ("A1", 1234567890111111);//Value load less than int type to receive length5 ...6Map<string,int> B1map =NewHashmap<string,int>();7B1map.put ("A1", 1234567890111111);//Value load less than int type to receive length8Map<string,int> B2map =NewHashmap<string,int>();9B2map.put ("A1", 1234567890111111);//Value load less than int type to receive lengthTen ... One  A intC1 = A1map.get ("a1") + B1map.get ("B1")); - intC2 = A2map.get ("a1") + B2map.get ("B1")); - if(C12.length () > A2map.get ("A1"). Length ()) { theC1 + = 1; - } -...

I thought about that, the first 500 bits of the number to split, and then split the number to add, here need to judge the carry, I do not know right and wrong, but this way is very troublesome. Finally the interviewer listened to me and said it was possible, but it was troublesome.
Finally he said to use the For loop traversal, and then let each number add, the result is reversed a bit, specifically let me go back to Baidu a bit. The rest is that he asked me to ask him questions, Then it was a chat about the company culture, and his understanding of the job, the time is quite long.




Three sides: Technology two side
Two-faced interviewer is a very funny person, this time he is on my pen questions and resume to ask some questions, ask the question is more extension of the problem.

Four sides: Personnel two
Here is more about the development of some companies, the company's treatment and I leave the main reasons.
This is usually a chat, and finally I agree to sign with them and then go straight into the next Monday.


Finally take advantage of these two days to have a good rest. Through these interviews really feel that they have too many deficiencies, a lot of basic knowledge of their own is not very solid. In the future work will certainly be more efforts to precipitate themselves.
If you have a recent interview with a small partner hope that my article can have some help to you, I wish you all can find your favorite company.

[Java plane] Two or three things about the interview.