The latest 32W-word Java engineer interview questions, it is enough for a big factory interview

foreword

The competition in the Internet industry is becoming more and more severe, and interviews are becoming more and more difficult. Many fans also privately asked me if I have a comprehensive set of interview questions.

This set of interview questions for Internet Java engineers includes: MyBatis, ZK, Dubbo, EL, Redis, MySQL, concurrent programming, Java interview, Spring, microservices, Linux, Springboot, SpringCloud, MQ, Kafka interview topics (485 pages in total, 32W words)

Due to space limitations, only interview questions can be shown

MyBatis Interview

What is Mybatis?
Advantages of Mybaits:
Disadvantages of the myBatis framework:
Applicable occasions of MyBatis framework:
What is the difference between MyBatis and Hibernate?
What is the difference between # and $?
What should I do when the attribute name in the entity class is different from the field name in the table?
How to write fuzzy query like words?
Usually an Xml mapping file will write a Dao interface corresponding to it. Excuse me, the working principle of this Dao interface is tDa
How does Mybatiz perform pagination? What is the principle of the paging plugin?
How does Mybati s encapsulate the execution result of sq into the target object and what are the mapping forms returned?
How to perform batch insert?
How to get the automatically generated (primary) key value? 14. How to pass multiple parameters in mapper?
What is the use of Mybatis dynamic sql? Execution principle? What kind of dynamic sql are there?
In the Xm1 mapping file, in addition to the common select |insert lupdae |delete tags, there are
Why is Mybati z a semi-automatic ORM mapping tool? What is the difference between it and fully automatic?
——to—,—to-many association query
MyBati s implementation - yes - there are several ways? How does it work?
MyBatiz implementation - there are several ways to many, how to operate?
Does Mybatiz support lazy loading? If yes, what is its implementation principle?
The first and second level caches of Mybati s:
What is the interface binding of MyBati s? What are the implementation methods?
What are the requirements when using the mapper interface of MyBatis?
What are the ways to write Mapper?
Briefly describe the operating principle of Mybati s plug-ins and how to compile

Zookeeper Interview

ZooKeeper interview questions?
What does ZooKeeper provide?
Zookeeper file system
ZAB protocol?
Four types of data node Znode
Zookeeper "atcher mechanism--data change notification
Client registration watcher implementation
Server-side processing watcher implementation
client callback atcher
ACL permission control mechanism
Chroot Features
session management
server role
Server working status under Zookeeper
data synchronization
How does zookeeper ensure the sequential consistency of transactions?
Why is there a Master in a distributed cluster? 16. How to deal with zk node downtime?
The difference between zookeeper load balancing and nginx load balancing
What are the deployment modes of Zookeeper?
How many machines are required for the cluster at least, and what are the cluster rules?
Does the cluster support adding machines dynamically?
Is Zookeeper's watch notification to the node permanent? Why is it not permanent?
What are Zookeeper's java clients?
What is chubby, what do you think compared with zookeeper?
Talk about a few commonly used zookeeper commands.
The connection and difference between ZAE and F axos algorithm?
Typical application scenarios of Zookeeper

Dubbo Interview

Why use Dubbo?
What are the layers of Dubbo's overall architecture design?
What communication framework is used by default, and are there other options?
Are service calls blocking?
What registry is generally used? Are there other options?
What serialization framework is used by default, and what else do you know?
What is the principle that the service provider can realize the invalidation? How can the old version not be affected when the service goes online?
How to solve the problem of too long service call chain? 10. What are the core configurations?
What protocol does Dubbo recommend?
Can I directly connect to a certain service when there are multiple registrations for the same service?
Draw-draw the flowchart of service registration and discovery?
How many solutions are there for Dubbo cluster fault tolerance?
Dubb. Service downgrade, how to do retry on failure?
Dubb. What problems did you encounter during use?
Dubbo Monitor implementation principle?
What design patterns does Dubbo use?
How is the Dubbo configuration file loaded into Spring?
What is the difference between Dubbo SPI and Java SPI?
Dubb. Does it support distributed transactions?
Can Dubbo cache the results?
How is the service compatible with the old version?
What are the packages that Dubbo must depend on?
What can Dubbo telnet command do?
Does Dubbo support service downgrade?
How does Dubbo shut down gracefully?
Difference between Dubbo and Dubbox?
The difference between Dubbo and Spring Cloud? Do you know other distributed frameworks?

Redis Interview

What is Redis?
Redis data type?
What are the benefits of using Redis?
What are the advantages of Rediz over Memcached?
What are the differences between Memcache and Redis?
Is Redis single-process or single-threaded?
What is the maximum capacity that a value of type string can store?
What is the persistence mechanism of Redis? What are the advantages and disadvantages of each?
Redis common performance problems and solutions: 10. Redis expired key deletion strategy?
Redis recycling strategy (elimination strategy>?
Why does ediz need to put all the data in memory? 13. Do you understand the synchronization mechanism of Rediz?
What are the benefits of Fipeline, why use pipeline?
Have you ever used Redi z cluster, what is the principle of the cluster?
Under what circumstances will the Redis cluster solution cause the entire cluster to be unavailable?
What are the Java clients supported by Redis? Which one is officially recommended?
What are the advantages and disadvantages of Jedi z compared with Redisson? 19. How to set password and verify password for Redis? 20. Talk about the concept of Redis hash slot:?
What is the master-slave replication model of the Redi z cluster? 22. Will some operations be lost in the Redi = cluster? Why? 23. How are Redi z clusters replicated?
What is the maximum number of nodes in the Rediz cluster? 25. How to choose a database for the Redis cluster? 26. How to test the connectivity of Redis? 27. How to understand Rediz transactions?
What are the commands related to Rediz transactions?
How to set the expiration time and permanent validity of Redis key?
How does Redis do memory optimization?
How does the Redis recycling process work?
What are the ways to reduce the memory usage of Redis?
What happens when Redis runs out of memory?
— How many keys can a Redis instance store at most? List, set and Sorted set can store at most
MySQL. There are 2000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 instances
What scenario is Redis most suitable for?
There are 100 million keys in Rediz, of which 10w keys start with a fixed known prefix. If it is
If there are a large number of keys that need to be set to expire at the same time, what do you generally need to pay attention to?
I have used Rediz as an asynchronous queue network. Mei Jingfu has a ?key, and there are 10w ke. fixed known prefixes.
Having used Redis distributed lock master is a needle art Shangshixue”

MySQL Interview

What kinds of locks are there in MySQL?
What are the different tables in MySQL?
Briefly describe the difference between MySAM and InnoDB in the MySQI database
The names of the four transaction isolation levels supported by InnoDB in MysQL, and the differences between them step by step?
What is the difference between CHAR and VARCHAR?
What is the difference between primary key and candidate key?
What is myisamchk used for?
What happens if a table has a column defined as TIMESTAMP?
How do you see all the indexes defined for the table?
What do the % and _ in the LTRE statement mean?
What is the column comparison operator?
What is the difference between BLDE and TEXT?
What is the difference between MysQL_fetch_array and MySQL_fetch_object?
Where will MyISAM tables be stored, and also in what format are they stored?
How does MySQI optimize DISTIHCT?
How to display the first 50 lines?
How many columns can be used to create an index?
What is the difference between Now() and CURRERT_DATE()?
What is a non-standard string type?
What is the universal sQI function?
Does MySQL support transactions?
What field type is good for recording currency in MysQL
What are the tables related to permissions in MySQL?
What can be the string type of the column?
The MySQI teaching database is used as the storage of the publishing system, and more than 50,000 entries per day are added. It is expected to be operated and maintained for three years.
lock optimization strategy
The underlying implementation principle and optimization of the index
Under what circumstances is the index set but not available
How to optimize MysQL in practice
How to optimize your database
Briefly describe the impact of the difference between indexes, primary keys, unique indexes and joint indexes on the performance of the database in MySQL.
What is a transaction in a database?
What Causes SQL Injection Vulnerabilities? How to Prevent?
Select the appropriate data type for the fields in the table
storage period
For relational databases, index is a very important concept, please answer a few questions about index:
Explain the difference between MySQL outer join, inner join and self join
Overview of transaction rollback mechanism in Myql
What parts does the SQL language include? What are the key operations in each part?
What are integrity constraints?
What is a lock?
What is a view cursor?
What is a stored procedure? What is used to call it?
How to understand the three paradigms in a popular way?
What is a base table? What is a view?
i try to describe the advantages of the view?
What does HUI.L mean?
The difference between primary key, foreign key and index
What can you use to ensure that a field in a form only accepts values within a certain range?
What are the methods for optimizing SQL statements? "Choose a few)

Java Concurrent Programming

What are the three elements of concurrent programming?
What are the ways to achieve visibility?
The value of multithreading?
What are the ways to create threads?
Comparison of the three ways of creating threads?
Thread state flow diagram
Java threads have five basic states
What is a thread pool? How many ways are there to create it?
Creation of four thread pools
Advantages of thread pool?
What are the commonly used concurrent I tool classes?
The difference between Cycli cBarr i er and CountDownLatch
What is the function of synchro oni zed?
The role of the volatile keyword
What is CAS
The problem with CAS
What is Future?
What is AQS
A0S supports two synchronization methods:
What is ReadYri teLock
What is FutuwreTask
The difference between synchro oni ze d and Reentr antLoc
What are optimistic locks and pessimistic locks
How does thread B know that thread A has modified the variables?
syn.chroni zed, volatile, CAS comparison
What is the difference between the sleep method and the wait method?
What is ThreadLoca1? What is it for?
Why wait 0 method and noti fy 0/noti fyAll(
method to be called in a synchronized block
What are the methods of multi-thread synchronization?
Thread Scheduling Policy
What is the concurrency of Concurr entHashMap
How to Find Which Thread Uses the Most CPU in the Linux Environment
Java deadlock and how to avoid it?
cause of deadlock
How to wake up a blocked thread
How do immutable objects help with multithreading
What is multithreaded context switching
What happens if the thread pool queue is full when you submit the task
What is the thread scheduling algorithm used in Java
What are Thread Scheduler and Time Slicing?
What is a spin lock
What is the Lock interface (Locker face) in the Java Concurrency API
Singleton thread safety
What does a Semaphore do?
What is the Executor class?
The construction method of the thread class and which thread the static block is used by
Synchronized method or synchronized block, which is better choice?
What exceptions will be caused by too many Java threads?

Spring Interview

What is spring?
What are the benefits of using the Spring framework?
What modules does Spri ne consist of?
The core container (application context) module.
BeanFactory- BeanFactory implementation example.
XMLBeanF actory
Explain the AOP module
Explain the JBC abstraction and DAD module.
Explain the Object/Relational Mapping integration module.
Explain the WEB module.
Sprinr configuration file
What is Spring IOC container?
What are the advantages of IOCs?
What is the usual implementation of Appli cati onContext?
What is the difference between Bean factories and Application contexts?
What does a Spline application look like? Dependency Injection
What is Dependency Injection in Sprine?
What are the different types of I0C (Dependency Injection) approaches?
Which dependency injection approach do you recommend, constructor injection or setter method injection?
What are Spring beans?
What does a Spring Bean definition contain?
How to provide configuration metadata to the Spring container?
How do you define the scope of a class?
Explain the scope of several beans supported by Spring.
Are singleton beans in the Spring framework thread-safe?
Explain the bean life cycle in the Spring framework.
Which are the important bean lifecycle methods? Can you override them?
What is the inner bean of Spri ne?
How to inject a java collection in Spring?
What is bean wiring?
What is bean autowiring?
Explain the different ways of autowiring.
What are the limitations of autowiring?
Can you inject a nu11 and an empty string in Spring?
What is the Java-based Sprine main solution configuration? Give some examples of annotations.
What is annotation-based container configuration?
How to enable annotation assembly?
@Required annotation
@Autowired annotation
@Qualifier annotation
How to use JDBC more effectively in Spring framework?
JdbeTemplate
Spring support for DA0
How to use Spring to access Hibernate?
0RM supported by Spring
How to combine Spring and Hibernate through HibernateDaoSupport?
Types of transaction management supported by Spring
What are the advantages of transaction management in the Spring framework?
Which type of transaction management do you prefer?
Explain AOP
Aspect section
In Spring AOP, what is the difference between concerns and crosscutting concerns?
Junction
notify
Cut-off point
What is import?
What is a target audience?
What is a proxy?
How many different types of automated proxies are there?
What is weaving. What are the differences in weaving applications?
Explain the aspect implementation based on the XML Schema method.
Explain annotation-based aspect implementation
What is Spr ine's MYC framework?
DispatcherSerlet
WebApplicationContext
What is a controller in the Spring MVC framework?

Kafka interview

How to get a list of topic topics
What is the command line for the producer and consumer?
Is the consumer pushing or pulling?
Talk about kafk's method of maintaining consumption status tracking
Talk about master-slave synchronization**
Why do we need a message system, can mysql1 not meet the demand?
What is the role of Zookeeper for Kafka?
What are the three types of transaction definitions for data transmission?
What are the two conditions for Kafka to judge whether a node is still alive?
There are three key differences between Kafka and traditional server messaging systems
Talk about the three mechanisms of kafks ac
Consumer failure, how to solve the livelock problem?
How to control the location of consumption
In the case of kafka distributed (not stand-alone), how to ensure the sequential consumption of messages?
What is the high availability mechanism of kafks?
How does kafka reduce data loss
How does kafka not consume duplicate data? For example, deduction, we cannot deduct it repeatedly.

Microservice Interview

What do you know about microservices?
What are the advantages of microservice architecture?
What are the characteristics of microservices?
What are the best practices for designing microservices?
How does the microservices architecture work?
What are the pros and cons of microservices architecture?
What is the difference between monolithic, SOA and microservices architecture?
What challenges do you face when using microservices architecture?
What are the main differences between S0A and Microservice Architecture?
What are the characteristics of microservices?
What is Domain Driven Design?
Why is Domain Driven Design (DDD) needed?
What is ubiquitous language?
What is cohesion?
What is coupling?
What is REST 1 RESTfu and what is it for?
What do you know about Spring Boot?
What is Spring Boot's Actuator?
What is Spring Cloud?
What problems does Spring Cloud solve?
What is the use of WebMvcTest annotations in a Spring MVC application?
Can you give the gist about rest and microservices?
What are the different types of microservice testing?
What do you know about Distributed Transaction?
What is I demopotence and where is it used?
What is a bounded context?
What is two-factor authentication?
What are the credential types for two-factor authentication?
What is a client certificate?
What is the use of FACT in a microservices architecture?
What is 0Auth?
What is Conway's Law?
What do you know about contract testing?
What is End-to-End Microservice Testing?
What is the purpose of Container in microservices?
What is DRY in microservice architecture?
What is a Consumer Driven Contract (CDC)?
What is the role of Web, REST ful API in microservices?
What do you know about semantic monitoring in microservices architecture?
How do we do cross-functional testing?
How can we eliminate indeterminism in testing?
What is the difference between Mock or Stub?
How Much Do You Know About Mike Cohn's Testing Pyramid?
What is the purpose of Docker?
What is a canary release?
What is Continuous Integration (CI)?
What is Continuous Monitoring?
What is the role of the architect in microservice architecture?
Can we create state machines with microservices?
What is Reactive Scaling in Microservices?