Since joining Ali from 2019.04.01, my work has been relatively busy, and I have hardly written any answer in the past year. Recently, the number of likes for this article has been increasing. Presumably, in the recent job search season, everyone has more demand for such articles. Combine yourself. In the past year, I have gained some new insights in my work. I decided to add some content to the original article and share it with you. If I have time, I will write a separate article. [About the interview question, the answer will be updated tomorrow]
In addition, I have compiled a list of the latest Java interview questions and core knowledge points, which can help you improve and advance your skills. Friends who need it can click: click this, click this , and the code: csdn.
The previous answer (in the part of the interview questions later), in retrospect, if you interview P5 and P6, it may be possible, but if you go further, these alone are not enough. Here are some abilities required from P6+ to P7 (just the idea):
Both technical depth and breadth
Computer core courses: computer network, data structure, computer composition principle, computer operating system, these courses need in-depth understanding (emphasis), jdk source code, pick some frameworks to take a closer look (such as Spring, Netty), common design patterns, some Middleware, such as MQ, ES, database: mysql, redis, etc. The above mentioned are basic skills. You can practice first when learning, and then look at the relevant theoretical knowledge in reverse to make these things clear and clear, and in the project On realization.
Business related
What is the technology stack of what you are doing right now? Which advantages and disadvantages? If you start from scratch, can it be realized again? Who is using the current system? How many users? When does the user concentrate? What data is left in the system? Who is using this data? Who is the relying party of the system? It is best to draw the relevant flowcharts from the perspective of technology, product, and business. Otherwise, whether it is an interview or ordinary work, and different parties to the needs, and even from the technology to achieve related functions, all aspects will be very passive.
Focus on skills when dealing with different roles
This point is also being summarized by myself. When dealing with products, businesses, operations, and technologies, we must know the boundaries of our responsibilities, figure out what needs to be done by ourselves, and what should be done by other parties. The communication is neither humble nor overbearing. This point involves core competitiveness, someday write a separate article!
I have been interviewing recently, but in half a year, only three people were recruited in the department. They communicated with other colleagues and summarized some commonalities of these interviewers. The most important thing to say to them is: take a good look at the basics! In the past, in other companies, the main focus was on engineering business capabilities. It can be said: It may be enough to write business code well for performance, but it is far from enough in Ali. If business code is written well, performance can only pass. Other KPIs It depends on what is done outside the business? It is said that the Dubbo framework is made by Ali employees for KPI (just heard)
Java is just a tool. As an engineer, you must have a considerable degree of mastery of the entire computer system; secondly, you must base yourself on engineering needs and think about solutions. Even if you are interviewing for a java position, there are many questions to ask if you are separated from java: data structure (array, linked list, Trees, graphs, sorting...), algorithms, caching applications, underlying principles of mysql database, spring source code (at least AOP and IOC), message queue design and use, and the deployment of these middleware in a distributed environment...
After all the above are familiar, it is necessary to realize that science is divided into basic science and applied science. Engineers must deeply understand the underlying implementation principles of application technology. In fact, from the perspective of personal development, application is essential, but the foundation is much more important than application. Yes, it’s just that companies need to produce quickly. In the trend of Internet development, most companies prefer skilled workers, but in the future, the cold winter has already been seen. The recruitment is much stricter than before, and the company pays more attention to interviews. It is expected that the inspection of basic knowledge will become more and more stringent in the future.
The above words are to remind everyone: Java is just a tool; applications are essential, but basic knowledge is what determines your own upper limit.
When I was looking for a job, I participated in the Java R&D interviews of many first-line Internet companies. This time was in the cold winter. However, a few days ago I changed jobs to find a job. I met 3 companies in two days. I already took two offers. I think I can share with you. :
The following are some java interview questions that impressed me deeply by companies such as Pinduoduo, Are you hungry, Ant Financial, Hello Travel, Ctrip, Are you hungry, 2345, Baidu, etc.
- Private modified methods can be accessed through reflection, so what is the meaning of private
- Java class initialization order
- Understanding of method area and permanent area and the relationship between them
- A java file has 3 classes, and there are several class files after compilation
- Local variables need to be assigned explicitly before they are used, otherwise the compilation will not pass, why is this design
- Is ReadWriteLock mutually exclusive between reading and writing?
- Semaphore is mutually exclusive between threads that have the right to execute
- Write a singleton pattern that you think is the best
- What kind of problems do B-tree and B+ tree solve, how to evolve, and the difference between
- Write a producer consumer model
- Write a deadlock
- How to locate cpu 100%
- String a = "ab"; String b = "a" + "b"; Is a == b equal and why
- int a = 1; Is it an atomic operation?
- Can a for loop be used to directly delete specific elements of an ArrayList? What might go wrong? How to solve
- New tasks are submitted to the thread pool, how is the thread pool handled
- Principles of AQS and CAS
- Synchronized underlying implementation principle
- Volatile role, instruction rearrangement related
- Principles of AOP and IOC
- How does Spring solve the problem of circular dependencies
- How dispatchServlet distributes tasks
- What problems will occur when mysql indexes the low-dispersion fields, and the specific reasons
Other frequently asked HashMap underlying implementation principles, conventional multi-threaded questions have been tested too much, so I won’t write them if there is nothing new.
Usually you can't just study with the purpose of applying Java. It is necessary to deeply understand the underlying implementation principle behind each knowledge point. Why is it designed like this? For example, if there is a hash for ranking, what is the function of equals()? You can still ask some people on this question, so you must dig out the details and really understand every knowledge point.
At last
Provide free Java architecture learning materials, learning technology content includes: Spring, Dubbo, MyBatis, RPC, source code analysis, high concurrency, high performance, distributed, performance optimization, microservice advanced architecture development, etc.
Friends in need can click: click this! Click this! , Code: csdn.
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Author: ZO01 link: https: //www.zhihu.com/question/60949531/answer/579002882