Preface
A small partner was sloppy in finding the first two jobs after graduation. Now he has graduated for three years and wants to find a job for a few years. So he has prepared for more than three months. Every day he is writing questions, watching videos, and reading books. I enriched my skills and finally got an offer from Ali Java Gang.
The following editor will share with you the problems encountered by this little partner during the interview, hoping to help everyone.
1. Opening
Briefly introduce your work experience and responsibilities, the main content of work at school or at work, and the content of main responsibility; (Your information is written in a clean resume on the resume, this is mainly to relieve the pressure of the interviewer)
Introduce your most satisfied project or platform with technical highlights, and focus on the technical details of the part that you are responsible for; (mainly examine whether the candidate has a clear description of what he has done, and judge the complexity of what he has done )
Two, Java multithreading
The principle of thread pool, why create thread pool? The way to create a thread pool;
The life cycle of the thread, when will there be a dead process;
Talk about thread safety issues, what to achieve thread safety, how to achieve thread safety;
What are the core parameters for creating a thread pool? How to reasonably configure the size of the thread pool?
The usage scenarios and principles of volatile and ThreadLocal;
When will ThreadLocal appear OOM? why?
The difference between synchronized and volatile, synchronized lock granularity, simulated deadlock scenario, atomicity and visibility;
Three, JVM related
JVM memory model, GC mechanism and principle;
What are the two types of GC, and what is the difference between Minor GC and Full GC? When will Full GC be triggered? What algorithm are used?
There are several classloaders in JVM, why are there multiple?
What is the parent delegation mechanism? Introduce some operational processes and the benefits of the parental delegation model;
Under what circumstances do we need to break the parental delegation model;
What are the common JVM tuning methods? Which parameter can be adjusted specifically and what value?
How the JVM virtual machine memory division, class loader, garbage collection algorithm, garbage collector, and class file structure are analyzed;
Four, Java Extension
Implementation principles and application scenarios of red-black trees;
What is NIO? What kind of scene is applicable?
What is the improvement of Java9 over Java8;
What is the data structure inside HashMap? How is the bottom layer implemented? (May also be extended to examine ConcurrentHashMap, HashMap, HashTable, etc., to examine the in-depth understanding of technical details);
Talk about the use and realization of reflection, is reflection very slow, and whether we should avoid using reflection in the project;
Talk about the scene and implementation of custom annotations;
The difference between List and Map, Arraylist and LinkedList, and ArrayList and Vector;
Five, Spring related
The realization principle and scenario of Spring AOP?
The scope and life cycle of Spring beans;
What improvements has Spring Boot made over Spring? What improvements have been made in Spring 5 over Spring 4;
How to customize a Spring Boot Starter?
What is Spring IOC? What are the advantages?
SpringMVC, dynamic proxy, reflection, AOP principle, transaction isolation level;
Six, middleware
Dubbo complete one-time call link introduction;
How many load balancing strategies does Dubbo support?
The Dubbo Provider service provider needs to control the upper limit of concurrent requests. What should I do?
How many configuration methods does Dubbo support when it starts?
Know several messaging middleware products? Introduction of the advantages and disadvantages of each product;
How does the message middleware ensure the consistency of the message and how to retry the message?
Introduction to Spring Cloud fuse mechanism;
Compared with Dubbo in Spring Cloud, in what scenarios should Spring Cloud be used?
Seven, database articles
Introduction to lock mechanism: row lock, table lock, exclusive lock, shared lock;
The business scenario and implementation of optimistic lock;
Introduction to transactions, understanding of distributed things, what are the common solutions, what are the two-phase commit and three-phase commit;
MySQL records binlog mainly includes three modes? What are the advantages and disadvantages of each mode?
MySQL locks, pessimistic locks, optimistic locks, exclusive locks, shared locks, table-level locks, row-level locks;
The principle of distributed transaction is two-phase commit, synchronous\asynchronous\blocking\non-blocking;
Database transaction isolation level, MySQL default isolation level, how Spring implements transactions,
How does JDBC implement transactions, nested transactions, and distributed transactions;
The entire analysis of SQL, the principle of the execution process, and SQL row conversion;
Eight, Redis
Why is Redis so fast? What are the problems with multithreading in redis?
Which data structures does Redis support;
Redis jump table problem;
How can Redis single-process single-threaded Redis be highly concurrent?
How does Redis use Redis to implement distributed locks?
How does Redis realize the atomicity of distributed lock operations?
9. Other
What source code have you seen? Then you will ask some detailed questions based on the source code you said? (This is mainly to examine whether the interviewer has the spirit of studying the technology, or just stay on the surface, or memorize a few lessons. For many interviewers with obsessive-compulsive disorder, if you have not even read the source code, it is basically Will pass off, such as me too!)
What are the more challenging problems encountered in the project, and how to solve them; (This is very controversial. On the one hand, you can’t even solve a complicated problem. What do you want you to do here, and how to solve it? , But the company does not have a business scenario for me to show, this depends on the interviewer you meet, good luck!)
to sum up
In fact, the scope of interview questions is not very large, but you still do not answer well. In the final analysis, it is the lack of knowledge system!
The editor here sorted out most of the interview questions and answers involved in the interviews of some major java programmers to share with you for free, hoping to help you, friends in need can see the free way to receive them below !
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Finally, thank you for your support, and hope that the information compiled by the editor can help you! I also wish everyone a promotion and salary increase!
