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The annual autumn recruitment drama is about to begin again. In recent years, the number of back-end jobs is increasing, and the pressure of graduates is also increasing. Personally feel that each large and medium-sized factory recruitment interview bad place is, are in the direction of back interview eight-part essay development (once interviewed a second-line factory, in front of the interviewer pure back 40 minutes concept), but have to admit that this is also an important means of enterprise in a short time to screen the interviewer.
In order to help you understand how to recite the backend interview essay, we hereby launch the interview essay drawing focus series (including the content of Java foundation, JVM, MySQL, Redis, operating system, computer network, design mode). Hope to help the Java foundation is not very good students can quickly prepare for the interview essay. In addition, I hope that after reciting the eight-part essay of the interview, we still need to understand more about the underlying principles. If you can naturally throw out some of your understanding of the underlying principles according to the questions of the interviewer in the interview, the interviewer will be particularly surprised.
In addition, we should learn more about the application of these knowledge points in practical scenarios. My favorite type of interview is when the interviewer presents a scenario and asks you to come up with a solution to that specific problem. If you can answer the interviewer’s question in the right way, based on what you’ve learned, and analyze why you’re doing it, it’s a big plus. I once chose the most appropriate data structure (using the idea of Bloom filter) to solve the interviewer’s scenario question in the interview with the supervisor of JINGdong, and the supervisor directly gave me the Special offer.
Interview skills
Here is an interspersed interview skills, because this is the beginning of the eight-part essay, more about it. You don’t have to memorize every interview question on the Internet to prepare for an interview. You can’t memorize so many questions on the Internet. First of all, you should make a plan when preparing for autumn recruitment, and plan which part of your preparation to what extent. For example, my plan is as follows:
1. Java based
Be familiar with Java and answer 90% of the interview questions. I prepared collections like HashMap and ArrayList, and I understood concurrent thread pools and locking mechanisms. When the interviewer asked me, I tried to answer some questions that he didn’t often hear from other interviewers.
2.JVM
Other common questions about JVM tuning should be answered clearly.
3.MySQL
Prepare MySQL. In addition to the MySQL common questions will be, for MySQL optimization to have a certain accumulation, here MySQL optimization skills are not limited to the interview, to give the interviewer to point face when fresh students do not often hear. MySQL has always been a hot topic in my interviews. Once an interviewer from a big factory talked with me about MySQL for a while and asked me how I learned it so well. Here is a recommended course, is Lin Xiaobin’s MySQL combat 45, I learned a lot from this course. Because this course is a paid course, they did not ask me to advertise, so I will not hang the link, if you are interested in it, you can find it by yourself
4.Redis
Redis focuses on preparation. What is Redis? What is Redis? What is Cache penetration? What is cache avalanche? B: well… I was a little more prepared than you. I fully understood the data structure of Redis, the persistence of Redis, and the design of Redis cluster, and brought the cluster to my project, and optimized the project to some extent by using the characteristics of cluster. This is also my interview killer.
- Computer Fundamentals
Spend less time on them. According to some of their own basis, plus with one or two days to put on the Internet such as three times shake hands four times wave of the face of the back on the back. When asked by the interviewer, the interviewer said that it would be good to only understand some of the most basic.
6. Project and design mode
I have prepared two projects, one is an e-commerce project and the other is a project to implement a simplified version of Spring framework. E-commerce projects are the generic Nginx + Redis + RabbitMQ + MySQL architecture, but I have made my own optimizations in these links based on my understanding of Redis and MySQL. Another project was to implement a simplified version of the Spring framework, where reflection, annotations, and design patterns were applied. When the interviewer asked me about design patterns, I said I was familiar with several design patterns used in projects.
In this way, their knowledge system is ready, in fact, through the formulation of the above plan, their resume is also written. Starting with the interview and introducing yourself, lead the interviewer into a familiar place. Once the interviewer asks a question that you have prepared in advance, I can tell him or her that he or she is off work.
Also, think before you answer a question, and never answer a question by mentioning something you’re not familiar with. Every time you mention something else, you’re setting yourself up for a big hole if you’re unfamiliar with it.
How to prepare Java interview essay good, said a little bit more in front, now return to the theme of this article, now this environment, essay is certain to back some. Baymax, give the interviewer the whole job by memorizing the interview essay
How to prepare for the interviewer to skillfully recite the Java interview essay? It takes two steps to prepare!
(1) To prepare for autumn recruitment, read books to learn basic Knowledge of Java.
(2) Prepare for the later stage of autumn recruitment, recite the interview essay according to the knowledge points frequently tested in the interview under the condition of having a certain grasp of the basic knowledge of Java.
Autumn recruitment preparation at this time, should be in dachang autumn recruitment about 2-3 months before the start, recommend everyone to follow the “Java Programming logic” to learn the basic knowledge of Java. Students with weak Java foundation should grasp this stage. While there is still time, while reading the book with the example of a knock on the book, the technology in the book with a use, experience Java programming ideas.
Why you should check it out: This book is really about Java in a nutshell. The content is deep, but the description is easy to understand. Highly recommended.
Learning Content:
The learning content is described in the Java Programming Logic.
Chapter 1: Programming basics
This chapter covers data types and variables, assignment, basic operations, conditional execution, loops, function usage, and basic principles of function calls. These are the most basic Java, certainly will.
Chapter 3: Class basics, Chapter 4: Class inheritance, Chapter 5: Class extension
This is a popular place for interviews. Encapsulation, inheritance, polymorphism, overloading, overwriting, and what can and can’t be inherited are often asked by interviewers. So these three chapters should be studied carefully. Experience object-oriented programming ideas, can also help you write high-quality code.
Chapter 6 Anomaly
This does not have to learn too much detail, but the basic exception to catch and throw is to learn, write code often need to use. Be familiar with common exception types.
Chapter 7 common base classes
Not only should you be familiar with the concept of strings, you should also be familiar with the operation of strings. Although most interviewers will allow you to look up apis during the process of tearing up code, you should try not to look up operations involving strings. The interviewer may think that your usual amount of code is too small. Basic understanding of other common base classes is good.
Chapter 9 -> Chapter 12 collections
The collection section is an uHF test point for Java back-end interviews. ArrayList, LinkedList, HashMap, queue operations need to be familiar, write code problems often use these containers. In addition, the realization principle of the above several sets, the data structure used to understand clearly, but also to experience the good design of these sets.
Chapter 15, Chapter 16, Chapter 17, Chapter 19, chapter 20 concurrent parts
The concurrent part is the uHF test point of each big factory interview. Synchronized, CAS, ReentrantLock, ConcurrentHashMap, and thread pools. To fully understand the realization of the above knowledge points, and remember the work flow of these knowledge points. Had better be able to see the application in actual scene of a few afore-mentioned examination spot additionally. If you can apply these techniques appropriately to your project and solve practical problems, the interviewer will be pleasantly surprised.
Chapter 21 -> Chapter 24
Reflection, annotations, dynamic proxies, class loading mechanisms
If you have time to learn, and then combined with the implementation principle of Spring to answer, can be used as your interview highlights.
Autumn recruitment preparation after the front of the basic knowledge of Java learning, we have basically mastered the basic knowledge of Java, then each big factory autumn recruitment resume channel has been open, want to understand each big factory autumn recruitment recruitment process and interview characteristics, please refer to my other article, “in order to uncover the Internet big factory autumn recruitment insider, I went through them all.”
Now we have to start the targeted back interview essay! Back interview to recommend a must see open source project (learn Java foundation and actual combat is also recommended to see this project), he is the famous JavaGuide, Guide brother! YYDS!
I will highlight and explain the content on JavaGuide so that you can have a look at it. The answers to the following questions can be found in JavaGuide. Here’s the link:
Snailclimb. Gitee. IO/javaguide / #…
The following knowledge points are to see, I through the star and bold way to the importance of knowledge points rating! The difficulty is aimed at the Internet big factory.
One star: not often asked in the interview, if the interviewer asked as far as possible to answer, answer does not matter.
Two-star: You are not often asked in an interview, but if the interviewer asks, you will lose points if you can’t answer your impression.
Samsung: You will be asked in the interview. The interviewer will wonder why you won’t either.
Four stars: interview frequency test point.
Five stars: Interview test points. Four – and five-star sites are the 10 interviews you’ll get in at least five of them. In the process of preparing for the interview, we try to answer these knowledge points clearly. The interviewer will open his back as soon as he asks.
1.Java language features (if you mention C++ on your resume, you may be asked about the difference between Java and C++). 【 ⭐ ⭐ 】
2. Compare the JVM with the JDK and JRE. 【 ⭐ ⭐ 】
3. Why is it said that the Java language “interprets and compiles”? 【 ⭐ ⭐ 】
4. What are the basic Java types and how many bits are there? 【 ⭐ ⭐ 】
A common interview question in previous years, only jingdong asked me in the interview process last year
Java generics, type erasure. 【 ⭐ 】
== equals(). 【 ⭐ ⭐ ⭐ 】
Before 2018, this question was almost a must-ask in an interview, but now it is rarely asked in large companies, and now it is more asked in small companies.
7. HashCode () and equals() 【⭐⭐⭐⭐】
This question is often asked, and interviewers often ask why do they override hashCode() when overriding equals()?
This question is often asked in conjunction with hashsets.
8. Difference between overloading and overwriting. 【 ⭐ ⭐ ⭐ ⭐ 】
9. Deep and shallow copies. 【 ⭐ 】
10. The difference between object-oriented and procedural. 【 ⭐ ⭐ ⭐ 】
11. Differences between member variables and local variables. 【 ⭐ ⭐ ⭐ 】
12. What are the three main features of object orientation? And explain these three characteristics. 【 ⭐ ⭐ ⭐ 】
13. The difference between String, StringBuffer, and StringBuilder 【 ⭐ ⭐ ⭐ ⭐ 】
14. The exception. 【 ⭐ ⭐ ⭐ 】
Don’t ask in great detail. Often ask what kinds of anomalies can be divided into, and then you answer the checkable and uncheckable anomalies, will let you give examples of what anomalies can be checked, what can not be checked.
And then the exception code will be written, there is a byte interview, just let me write a code that catches the exception and throws it.
15. Serialization and deserialization [⭐⭐]
16. Difference between List, Set and Map. 【 ⭐ ⭐ 】
17. Differences between ArrayList and LinkedList. 【 ⭐ ⭐ ⭐ ⭐ 】
Understand what data structures are used for each and compare the advantages and disadvantages.
18. Differences between HashMap, HashTable, and ConcurrentHashMap. 【 ⭐ ⭐ ⭐ ⭐ ⭐ 】
Now the interview of the UHF test site. When the interviewer asks you this question, it’s your chance to show off your ability to memorize the eight-part essay.
You can expand on what data structures are used for HashMap in Java7 and 8, why Java8 has changed from header to tail, how expansion is implemented, why the load factor is 0.75, why red-black trees are used, and so on. As long as the interviewer doesn’t interrupt me, I can recite this knowledge until the interviewer leaves work. I’m planning to write an article on this topic soon.
19. The difference between processes and threads. 【 ⭐ ⭐ ⭐ ⭐ ⭐ 】
This is a very high frequency question, and when you answer an interview you don’t have to say that a process with many threads is gone.
Should answer clear what is a thread what is a process, the running state of thread and process respectively, the communication mode of thread and the communication mode of process.
20. How to create a thread. 【 ⭐ ⭐ ⭐ ⭐ 】
Not only should you memorize how to create threads, remember the pros and cons of each approach, but you should also be able to write code. Some interviewers will ask you to write code to create two threads and then do something, such as output numbers alternately.
21. What are deadlocks, how they occur, and how they can be avoided. 【 ⭐ ⭐ ⭐ ⭐ ⭐ 】
Uhf questions, almost big factory side and side will be asked.
22. Synchronized lock upgrade process. 【 ⭐ ⭐ ⭐ ⭐ ⭐ 】
This is a big test point of the interview, lock upgrade process remember clearly.
23. The volatile keyword. 【 ⭐ ⭐ ⭐ ⭐ ⭐ 】
Contrast and synchronized.
24. The difference between optimistic and pessimistic locks. 【 ⭐ ⭐ ⭐ ⭐ ⭐ 】
25. A ThreadLocal. 【 ⭐ ⭐ ⭐ ⭐ 】
This is also a high-frequency test point of the interview essay. I don’t want to back the interview here, the interview process as far as possible to hide this knowledge point, do not mention and this related, actually really past.
26. Thread pools. 【 ⭐ ⭐ ⭐ ⭐ ⭐ 】
Uhf test point. You need to answer what kind of thread pool there are, the advantages and disadvantages of various thread pools, important parameters of the thread pool, the execution process of the thread pool, the saturation strategy of the thread pool, how to set the size of the thread pool, etc. I can recite it here for ten minutes.
27. Already and AQS. 【 ⭐ ⭐ ⭐ ⭐ 】
In fact, I was not very familiar with it during the interview, so I tried not to mention it and even passed it. So if you have enough time to understand this one better. If you have a good understanding here, you can talk to the interviewer for a long time.