For example, if you say that your company uses Dubbo as a service framework, you will be asked what is the underlying communication framework of Dubbo? Netty? Mina?

And then ask you what is the underlying NIO? What are long and short connections in network communication?

Have you seen the source code for Dubbo? What are the most impressive uses of concurrency in dubbo’s source code?

Some interviewers like to start by asking about the skills on the project, while others will start by asking about the skills on your resume, moving from the skills to the project. It’s a matter of personal preference.

Of course, there will always be some business details of the project at the end of the day, and good interviewers will learn to stick to the details.

When you ask questions, you have to go into the details of a particular business, and how the implementation and design of the technical solution combined with the details of the business, how to use various technologies in the business.

For instance

● You say you use Redis, which leads to further questions about which business you use Redis. Would you please describe the process of that business?

● What data structure do you use to store what data in Redis? What is the expiration time of the data? If the cache expires, what is your data bottom-of-the-line solution and where do you go to retrieve it?

● How and why is your key designed? This business of yours put the data in Redis. Which other business will check Redis? Why do you do it this way? What happens if you don’t use Redis?

This is just one example of how various techniques can be used to drill down into the details of a project. This will show you how much experience you have with the technology, how much experience you have with the online business, and what problems you can handle with a technology in an online system.

In summary, from the project, we can see whether you are responsible for the design and development of distributed systems under complex business architecture?

Is your system the challenge of online high concurrency high traffic high load scenario, have you experienced this technical challenge?

Do your systems handle the challenges of massive data storage and high performance read and write, and have you solved these problems?

In addition, from the project inspection, you can also directly see your overall ability and technical positioning. Have you been responsible for only one module? Or was it responsible for a subsystem?

Or as an architect responsible for a complete project group, leading a team of dozens of people and designing large-scale complex system architectures?

Therefore, what kind of projects and abilities you have controlled can be seen directly from the projects you have been responsible for.

If you come to interview for an intermediate position, we may think that your overall skills are ok. You have independently been responsible for the development of core modules, and you have certain practical experience in various technologies.

If you are in a senior/senior position, we will look at whether you have led a small team to independently design and develop the architecture of a complete system with some complexity and difficulty.

If you are interviewing for an architect position, you are expected to have led large, complex projects with many people working together in a company.

And we require you to have deep thinking and overall control of a large system architecture, and this project should have enough technical challenges, large users, high concurrency, massive data, and so on.

Therefore, project investigation is a top priority. Many students have accumulated a lot of technical learning, but there is a big problem is that there is too little project experience and practice.

These students may indeed have no experience in the architecture design of complex systems, so it is very easy to have problems in the project experience inspection and be judged by the interviewer as having good skills but lacking experience.

Three, the investigation of system design

This is also a lot of Internet big factory interviewers, in the investigation of some senior engineers and above the students, like to ask.

They usually take some business scenarios from their own company or team, or some common business scenarios, and then ask you how to design the system architecture for this business scenario?

A few examples:

• How to design an e-commerce kill system architecture?
• How to design a message push system architecture?
• How to design the system dynamic capacity expansion/reduction mechanism during the Double 11 promotion?

Similar and so on some scenarios of the system design investigation. In fact, this is mainly about using some scenarios that you may not have been exposed to, to test your architectural design thinking.

Especially for the above senior/senior, architecture positions, we will pay particular attention to the site of the business scenarios you have not been exposed to the architecture design.

Because after all, when you arrive, you must be exposed to new business, and then immediately give a reasonable and reliable architecture design scheme, in the new company to implement your experience.

Many students usually do not pay attention to the accumulation of system design ability, resulting in out of the interview, someone asked the scene system design problem, directly confused.

So, think about the various business scenarios in your company and set some challenges for yourself. For example, if your company’s requests and data volume increase 100 times, how would you design your system architecture?

Set yourself more challenges and try to think about design, so as to accumulate the thinking and ability of system design.

Four, the investigation of basic skills

Many big companies look at candidates’ basic skills, especially data structures and algorithms. For example, hand write some common algorithm problems on the spot.

Many students are easy to fall in the basic skills, some basic data structure and algorithm can not write, that is a bit of a problem.

It is important to note that this is not just for college graduates, but represents the basic technical literacy of an engineer, or even an architect.

Therefore, it is suggested that we should pay attention to the maintenance of basic skills, usually write algorithm problems, familiar with the data structure, can maintain their technical literacy will not fall.

Otherwise, the data structure and algorithm are not familiar with the technical details of the complex system can not control the basic, because a lot of complex distributed system source code, everywhere is their own data structure and complex algorithm.

Resume background/educational background/past experience/comprehensive quality

At the end, be sure to take a look at the candidate’s overall background, such as your resume.

● You used to work in an outsourcing company? Or from a traditional IT company? Or some small Internet company? Or a second tier of big Internet companies?

● And what about your educational background? Is college? General undergraduate? 211/985 undergraduate? General master’s? Master’s degree or PhD from 211/985 university?

● You used to work on internal systems, such as OA systems, accounting systems? Or are they all C-side systems with tens of millions of users? Or have you worked on some sort of off-track project in the past, like crawlers?

● How are your communication skills? Is the character dependable and nice, not impetuous? Are you a team player?

All these comprehensive things will be taken into consideration in our overall investigation, and we will decide whether to send an offer or not.

Six, the matching of candidates and post needs

In fact, after the above process inspection, will experience multiple rounds of interviews, basic a good interview can be comprehensive inspection of a candidate’s complete situation.

Is the candidate’s technical profile complete and has enough depth in several technical areas?

What kind of projects the candidate has done, what is the practical experience of the project, how many large teams and how big the project is,

How about the system design ability, basic skills, comprehensive background and quality of the new business scene? Basically, all these things can be examined very well.

At this point, a candidate will be matched with the needs of the job, for example, you are recruiting a senior Java position, who is needed to develop the core subsystems of the company.

Next, your tech stack is Dubbo, ZK, Kafka, Redis, etc

Your company has tens of thousands of concurrent access pressure per second, data volume of more than 100 million, the online system occasionally failure, such as high concurrency zK suddenly error abnormal, resulting in system business interruption, and then need to bring four primary and intermediate brothers together to develop.

At this point, you will know whether a candidate has the technical ability to match the position and the technical depth to cover some of the common faults of the online system.

Has sufficient source code expertise to analyze, locate, and resolve problems immediately in the event of an online failure. Do you have experience with projects with sufficient high concurrency and high volume data?

Have you led several people to independently control the architecture design and development of a core system? What are your previous company background, educational background and comprehensive quality?

Whether the candidate and the job needs to match, basically come out.

Seven, the division of labor and cooperation of multiple rounds of interviewers

There are a lot of technical tests listed above that can hardly be said to have been done directly by a round of interviewers.

Therefore, we are generally divided into multiple rounds of interview team investigation. But depending on the company, different rounds of interviewers may have slightly different responsibilities.

For example, the interviewer may focus on the technical content, including the technical side and a barrage of questions to investigate the technical depth, as well as the algorithm foundation, not very related to the project.

The second interview may focus on project experience, system design, and technical depth.

Three interviewers may look at you in terms of the size of projects you’ve managed, the size of teams you’ve led, team management skills, specifications and process design skills, overall work history and experience, soft qualities (communication, presentation, teamwork, values, etc.).

The above is just a kind of division, different teams within a company may have different division of labor.

Also some may be one or two is to inspect the technical surface and technical depth, does not involve the project, three to inspect your project experience, four to inspect some of your comprehensive quality.

Or maybe you’re up for a very senior position, like chief architect, or maybe a CTO or VP of technology is interviewing you for the fifth round.

But no matter how divided, the whole content is the above things and that process and process.

Java Advanced Interview series begins

In the next article, we will start to serialize the technical points frequently investigated in Java interview of medium and large Internet companies and relevant interview skills.

Stay tuned: Why do you want message-oriented middleware in your system architecture, guys? What are the disadvantages of introducing message-oriented middleware into a system architecture?

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