2021 Java Spring Recruitment Interview Guide: JVM + Concurrency + MySQL + Network + Spring (1 to 5 years must see)

2021 is coming soon, and it’s a good season for job-hopping. The students who are ready to switch jobs are all gearing up to prepare for several games. Today, I have prepared the interview questions that are necessary for Internet interviews for 1 to 5 years of Java interviewers. Respectively JVM, concurrent programming, MySQL, Tomcat, network and IO and Spring series, etc., it can be said that it is possible to master these salary increases by 10K!

Today, I will share with you all the most frequently used interview question banks in mainstream companies. They are also the latest answers after the Java version is upgraded, which will save the interviewees many unnecessary detours. At the same time, detailed interview analysis documents have been done for each topic to ensure that readers at each stage can understand it.

Java virtual machine 26 questions

What is the relationship between JDK, JRE, and JVM?

JVM memory model and partition situation and role

What is the process of creating JVM objects?

How many types of garbage collection algorithms are there? What are their corresponding advantages and disadvantages?

Briefly introduce what is the class loading mechanism?

What is the loading process of the class? Briefly describe each step

What kind of pre-defined class loaders are there for JVM? What are the roles?

What is the parental delegation model? what's the effect?

What is a Class file? What are the main information structures of the Class file?

What is the concept of "object is dead"?

How does the Java language achieve cross-platform?

What will cause OOM in the JVM data runtime area?

Introduce in detail the allocation process of objects in the zoned memory area?

Comparison of G1 and CMS garbage collectors

What are the JVM parameters commonly used online?

When did the subject enter the old age?

What is memory overflow, memory leak? What is the difference between them?

What are the behaviors that cause class loading operations?

Introduce the common tools provided by JVM

What is the difference between Full GC, Major GC, and Minor GC?

When is Full GC triggered?

Under what circumstances will stack overflow

Talk about strong references, soft references, weak references, phantom references and their relationship with gc

What is the proportional distribution of Eden and Survivor? why?

What to do if CPU resource usage is too high

OOM troubleshooting

At the same time, there are also the JVM study notes and study route map that I have compiled. It explains the learning content and actual combat notes of the JVM in detail. Friends in need please like it and add a concern. Click here to get the information for free. !

The content is divided into five or six modules

JVM memory area division

JVM execution subsystem

Garbage collector and memory allocation strategy

Write efficient and elegant Java programs

Performance optimization

JVM and performance optimization study notes. Xmind

25 concurrent programming in Java

Have you used Synchronized and what is its principle?

You just mentioned acquiring the lock of an object. What exactly is this "lock"? How to determine the lock of an object

What is reentrancy, and why is Synchronized a reentrant lock?

What optimizations has JVM made to Java's native locks?

Why is Synchronized an unfair lock?

What is lock elimination and lock coarsening?

Why is Synchronized a pessimistic lock? What is the realization principle of optimistic lock? What is CAS?

Is optimistic locking necessarily good?

Compared with Synchronized, what is the difference in the implementation principle of Reentrantl ock?

So please talk about the AQS framework?

Please compare the similarities and differences between Synchronized and ReentrantLock as much as possible.

How does Reentrantl ock achieve reentrancy?

Apart from ReetrantLock, which concurrency tools in JUC have you been exposed to?

Please talk about how ReadWriteLock and StampedLock make Java threads synchronize with each other? Which synchronizers do you know about? Please introduce separately

CyclicBarrier and CountDownLatch look very similar, please compare?

For concurrent programming, the editor only shows 15 questions, divided into 5 modules. These can be 90% of the questions asked by large companies on one side and two sides. I have made a detailed explanation here.

MySQL database 20 questions

Catalog display

For these 20 high-frequency problems, I made a very detailed analysis. At the same time, for MySQL and optimization, there is a note map here, and each node has a note record!

Network 20 questions

What are the HTTP response codes? What do they mean?

What is the difference between Forward and Redirect?

How to achieve cross-domain?

Tell me about the principle of JSONP implementation?

What is the difference between get and post requests?

Briefly describe the difference between TCP and UDP?

Why does TCP need a three-way handshake, can't it work twice? why?

Talk about how TCP sticky packets are generated? How to solve the sticky bag problem?

How does TCP ensure reliability

What is the difference between congestion control and flow control?

What are the seven-layer models of OSI?

The entire process of a web browser accessing a URL?

Explain the sliding window algorithm

Detailed process of domain name resolution

There are several types of IP addresses. What does each type represent and what is a private network?

Synchronization and Asynchrony in Computer Network

What should I do if I find that Baidu cannot be uploaded?

What is the difference between Cookie and Session?

What is the difference between HTTP 1.0 and 1.1?

The main difference between HTTP and HTTPS?

For these 20 high-frequency problems, a very detailed analysis was made

Spring series 100 questions

What is the Spring Framework? What are the main modules of the Spring Framework?

What are the benefits of using the Spring framework?

What is inversion of control (IOC)? What is dependency injection?

Please explain the loC in the Spring framework?

What is the difference between BeanFactory and ApplicationContext?

How many ways to configure Spring?

How to configure Spring based on XML configuration?

How to configure Spring in a Java-based configuration?

How to configure Spring with annotations?

Please explain the life cycle of Spring Bean?

What is the difference between the scope of Spring Bean?

What are Spring inner beans?

Are singleton beans in the Spring framework thread-safe?

Please give an example of how to inject a Java Collection in Spring?

How to inject a Java.util.Properties into Spring Bean?

Please explain the autowiring of Spring Bean?

Please explain the difference in auto-assembly mode?

How to turn on annotation-based automatic assembly?

Please give an example to explain the @Required annotation?

Please give an example to explain @Autowired annotation?

What is the difference between constructor injection and set value injection?

What are the different types of events in the Spring framework?

What is the difference between FileSystemResource and ClassPathResource?

What design patterns are used in the Spring framework?

For the Spring series of questions, only 24 questions are shown, and the remaining questions about SpringBoot, Spring Cloud, etc. are also analyzed in detail

Due to the content of the materials and the limited space on the platform, the editor showed some of the interview topics and materials above. For students who want to obtain all the interview materials below, click here to get the materials for free!

**Benefits and bonuses: ** 498 pages of Java architecture advanced interview analysis notes include ( Java, MyBatis, ZooKeeper, Dubbo, Redis, MySQL, Spring, Spring Boot, Spring Cloud, RabbitMQ, Kafka, Linux, etc. , ) I hope everyone can find a company that suits them and have a happy code.