Golden nine silver ten is the recruitment season, xiaobi here also to you a set of ali interviewers like to ask the most questions or high attendance interview questions, to help school recruitment or social recruitment on your way!

First of all, we need to understand the fact that one of the key factors in recruitment is to find future colleagues for themselves. At the same level, we need to find people who are better than ourselves. Interview is a two-way selection process, and it is also a process of heart-to-heart communication.

For example, some of us feel that they are very awesome, but can not get the offer, while others can get the offer with a dish, we call it metaphysical offer. In this case, we should not feel what can not be described, just follow the fate!

As before, only questions without reference to the answer, you need to learn down one by one!

1. Opening Remarks

  • Briefly introduce your work experience and responsibilities, the main work content in school or work, the main responsible content; (Your information is clearly written on your resume, which is intended to relieve the pressure of the interviewer.)

  • Introduce the project or platform with technical highlights that you are most satisfied with, and highlight the technical details of the part that you are responsible for. (The main test candidates to do their own things have a clear description, judge the complexity of the things to do)

Second, Java multithreading related

  • Why create a thread pool? How to create a thread pool;

  • The life cycle of a thread, when dead processes occur;

  • Talk about thread safety, what is implemented and how to implement thread safety;

  • What are the core parameters for creating a thread pool? How to size thread pools properly?

  • Usage scenarios and principles of volatile and ThreadLocal;

  • When will ThreadLocal get OOM? Why is that?

  • Synchronized, volatile, synchronized lock granularity, simulated deadlock scenarios, atomicity and visibility;

Third, JVM related

  • JVM memory model, GC mechanism and principle;

  • What are the differences between Minor and Full GC? When does the Full GC trigger? What algorithms are used?

  • There are several classloaders in the JVM. Why more?

  • What is the parent delegate mechanism? Describes some of the operational processes, benefits of the parental delegation model;

  • When do we need to break the parental delegation model;

  • What are common JVM tuning methods? What parameters can be adjusted and what values can be adjusted?

  • How the JVM memory partition, class loader, garbage collection algorithm, garbage collector, class file structure is resolved;

Iv. Java Advanced Section

  • The realization principle and application scenario of red-black tree;

  • What is NIO? What scenarios are applicable?

  • What Java9 improves over Java8;

  • What is the data structure inside a HashMap? How is it implemented at the bottom? (ConcurrentHashMap, HashMap, HashTable, etc., may also be extended to explore the depth of understanding of technical details);

  • Talk about the use and implementation of reflection, whether reflection is slow, and whether we should avoid using reflection in our projects;

  • Talk about the scenario and implementation of custom annotations.

  • List differs from Map, Arraylist differs from LinkedList, Arraylist differs from Vector;

Fifth, Spring related

  • Spring AOP implementation principles and scenarios?

  • The scope and lifecycle of Spring beans;

  • What improvements does Spring Boot have over Spring? What improvements Spring 5 has made over Spring4;

  • How to customize a Spring Boot Starter?

  • What is Spring IOC? What are the advantages?

  • SpringMVC, dynamic proxy, reflection, AOP principles, transaction isolation level;

Middleware

  • Dubbo complete a call link introduction;

  • How many load balancing strategies does Dubbo support?

  • How does the Dubbo Provider service Provider control the maximum number of concurrent requests to be executed?

  • How many configurations does Dubbo support when starting up?

  • How many messaging middleware products do you know? The advantages and disadvantages of each product;

  • How does messaging middleware ensure message consistency and retry mechanism?

  • Spring Cloud circuit breaker mechanism;

  • In contrast to Dubbo, when should Spring Cloud be used?

7. Database

  • Lock mechanism: row lock, table lock, exclusive lock, shared lock;

  • The business scenario and implementation of optimistic lock;

  • Transaction introduction, understanding of distributed things, common solutions, what is two-phase commit, three-phase commit;

  • MySQL records binlogs in three different ways. Okay? What are the pros and cons of each mode?

  • MySQL, pessimistic lock, optimistic lock, exclusive lock, shared lock, table level lock, row level lock;

  • Principle of distributed transaction 2 phase commit, synchronous, asynchronous, blocking, non-blocking;

  • Database transaction isolation level, MySQL default isolation level, how Spring implements transactions, how JDBC implements transactions, nested transaction implementation, distributed transaction implementation;

  • The whole SQL analysis, execution process principle, SQL row column;

Eight, Redis

  • Why is Redis so fast? What are the problems with using multiple threads in Redis?

  • Which data structures Redis supports;

  • Redis skip list problem;

  • Redis Single-process single-thread Redis how can high concurrency be achieved?

  • How to use Redis to implement distributed locks?

  • The atomicity of distributed lock operations in Redis, how is it implemented internally?

Nine, other

  • What source code have you seen? And then ask some detailed questions based on what you said about the source code? (Here is mainly to investigate whether the interviewer has the spirit of technical research, or just stay on the surface, or recite a few interviews, this for many obsessive-compulsive interviewers, if you have not even read the source code, basically will pass, for example, I am so!)

  • What are the challenging problems encountered in the project and how to solve them? (This is very controversial, on the one hand, you can not even solve a complex problem, why should you come here, and on the other hand, MY ability is great, but the company has no business scenarios for me to show ah! It all depends on the interviewer you meet. Good luck!

So far, roughly put some high-frequency interview questions sorted out, I hope to help you!

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