Writing in the front

I majored in microelectronics science and Engineering and learned a little Java. The project is a pure CRUD project and I have never touched RPC project. The following is the interview of four departments of Ali, which made the leaders laugh

2.24 Taobao shopping cart pre-surface 64 min (over)

To introduce myself

How will the school divide the time between study and internship?

What does the internship program do? Difficulties encountered?

What are the difficulties of the project in the lab?

The difference between JPA and MyBatis? Talk about object field mapping in detail

Some differences in MySQL indexes

What is a cluster index? What is a non-clustered index?

How does Innodb guarantee crash recovery? (Two-phase log commit)

What are Innodb’s strengths and weaknesses? (Talk about index number)

Index coverage? Back to the table? Unique index? Non-unique index? Leftmost principle?

What fields are in explain?

An SQL query is slow. Where should it be optimized?

What is the difference between an autoincrement ID and a UUID? (Leaf division)

What happens when the auto-increment ID application is completed?

What problems do repositories solve? What problem does the subscale solve?

What do you think are the basic requirements for learning Java? What is particularly important?

Seven-layer network model

Why the concept of seven floors and five floors?

JVM Memory Model (Overview)

Talk about parental delegation. Why?

What do you think is wrong with the name parental delegation? Tell me what you understand

What is an example of breaking parental delegation? How to break it?

What GC collector are you using now?

Object reclamation policy in Eden?

STW of CMS?

When does the CMS trigger the Full GC?

Do new objects always come out in the new generation?

What are the new GC algorithms for Java8?

Do you know the G1 collector?

One’s deceased father grind? Why does the current intern want to quit?

The difference between Golang and Java?

Rhetorical question: what can be improved?

2.25 One side of Taobao shopping cart for 50 min (pass)

What questions were asked in the last interview?

When is the internship coming?

Pick a problem or two that you encountered during your internship or project? Tell me how to solve it?

Have you thought of any areas of code that you could optimize in the project?

When will OOM appear?

How much memory is allocated in the heap?

Next-generation GC workflow?

Why is the Cenozoic age 15 times older?

Big object into the old age, this big object is how big?

How to check OOM?

What middleware are you currently using?

Does RPC understand?

What current problems does RPC solve?

Have you ever thought about turning your project into RPC?

What is the IOC initialization process?

How does AOP integrate with IOC?

How are circular dependencies resolved?

How are projects layered?

What is the difference between JPA and MyBatis? The principle?

How to optimize the performance of database hotspot query data?

Innodb index tree data structure?

Leftmost principle?

Are there any other complicated projects?

What do you know about troubleshooting?

What are your strengths?

Nailing side for 72 min (over)

To introduce myself

Introduce the program and internship

What is your understanding of RPC?

The relationship between HTTP and RPC? The difference between them?

The advantages of RPC?

Will any incoming request be called to the registry?

Some questions about the program and the internship

HDFS?

What about streaming in Java?

A process for SpringMVC to handle requests?

Listeners and interceptors for servlets?

What are some ways to intercept an HTTP request?

Do you have a way of summarizing parameters for accepting requests?

What other projects did you do in school?

What do you think is the most important thing to learn Java?

What is your understanding of IOC?

How are the various implementations of AOP different?

Why are there multiple ways of proxy?

HTTPS key exchange process?

What if there’s an intermediary hijacking?

Parental delegation understanding?

Why do parents delegate? Do I have to follow the parent delegate?

How to break parental delegation?

One thread is waiting for another thread to finish?

One thread is waiting for all the other threads to be ready?

Print ABC sequentially?

Innodb index data structure? Why use B+ trees?

One bottle of poison. Understand all understand.

Mass data take top 5.

3.04 Service Center stage one 52 min (pass)

To introduce myself

Have you met with other departments?

Introduce your internship program?

Some questions about the project

Is there anything else you think you can do better?

Why Golang for TX? (How do I know?)

DNS Resolution process?

How to resolve a domain name? What information is needed to resolve a domain name?

Why Nginx?

What do you see as the biggest use of Nginx in your project?

HTTPS key exchange process?

Do you think there will be problems with HTTPS? What if something goes wrong?

What is the difference between plugged-in Tomcat and Tomcat embedded in SpringBoot?

Do you know the design pattern of Tomcat?

How does SpringBoot start Tomcat?

What is your understanding of IOC?

Where do you actually use Bean pre – and post-handlers in your development?

How does AOP integrate with IOC?

How does Spring initialize Java objects into Spring Beans?

HashMap?

When does a Full GC occur?

How do I set the size of the method area?

How to set stack size?

Have you ever run into a stack overflow? How did it work out?

MySQl primary/secondary cluster

How many binlogs are there? What’s the difference?

3.05 Service Center Second Plane 75 min (pass)

The interviewer came up and spent 10 minutes introducing their department

Questions about Github projects (this code was written in the first half of my sophomore year)

How did you design the database in the project?

How are projects layered?

What happens after the traffic hits SpringMVC?

Wechat small program login process?

JS SDK login and backend request wechat server login difference?

Do you think raw information obtained from wechat login can be hijacked by hackers?

Do you use an overwatch? What are the problems solved by the database and table?

How to design primary keys when dividing tables?

Have you used custom indexes in your own projects?

Leftmost principle? Joint index?

Why is there the leftmost match rule? (Answer according to B+ tree sorting rules)

Why use B+ trees? Back to the table? How to reduce back table?

Optimistic and pessimistic locks for databases?

What is the difference between a read lock and a write lock?

Suppose you have a requirement to update a row in a for loop 100 times in a row, and block in the process? How do you code around this? (Manually inherit AQS)

How to close long transactions?

Why do you want to come to Ali?

How are microservice instances suspended? Understand?

Questions about internships and programs

What are the meanings of the 7 parameters in the thread pool?

Thread pool submission process?

How much do you know about distribution?

3.05 Nailing on the second side for 50 min (over)

I forgot to record the interview. I can’t remember some questions.

Some questions about the program and the internship.

A distributed deployment project? What are the minimum modules required?

Will any incoming traffic be called to the registry?

What is the minimum requirement for a registry?

A large amount of traffic is always sent to an instance, the sibling of the instance gets very little traffic, how to do?

What if an instance fails?

What if one of the registries dies while clustering?

What channels do you usually study through?

What blogs do you read?

Which of meituan’s blog posts do you find particularly helpful?

Then I talked more about this blog post

Where do you usually watch videos? What kinds of videos do you watch?

Can you recommend a public account about technology to me?

Have you read some of Ali’s tech blogs? Do you find their blogs helpful?

The rest of the eight-part essay problem does not remember…..

3.05 Taobao shopping cart second surface 60 min (pass)

This round of interviews also forgot to record….

To introduce myself

Some questions about the program and the internship

HashMap put contains 100000 data. If you put the 10000th data into HashMap put, will you expand the number?

What problems do you think are solved by using linked lists and red-black trees?

Of all data structures, why red black trees?

How do I balance a red-black tree?

How do you figure out the threshold for a linked list to become a red-black tree?

Why is the retracted list threshold for red-black trees different from the threshold for evolution?

What are the methods of code synchronization now encoded?

The Realization of Fair Lock and Unfair Lock

What are the characteristics of volatile?

Does a volatile variable, one thread writes, and multiple threads read cause thread insecurity?

What is the IOC initialization process?

Java class loading process?

Why is there a TIMEWAIT?

Congestion control? Flow control?

There are 1 trillion taobao orders, and each order contains a transaction flow, in which there is the ID of the product and the purchase quantity. The same product will appear many times in this order. Now we want to count the 10 products with the best sales.

That’s all I can remember…..

3.06 Financial Side of New retail Scenario 70 min (over)

Why not get a hardware-related internship to do software?

Can you introduce to me what the major of microelectronics science and engineering does?

How did you learn this stuff about software development?

Questions about internships and programs

What are some features of object orientation?

Java 7 Principles?

What’s the difference between procedural and object oriented?

The relationship between objects and classes?

Java container

A HashMap eight-part essays

What’s the difference between a process and a thread?

How does Java create threads?

Thread pool parameters and task submission to execution process?

Do you have your own set of thread pool parameters?

What about code synchronization?

Java class loading process? When is the loading of a Java class triggered back? When is the uninstallation of a class triggered?

Parental delegation? Break parental delegation?

How are overloads and overrides differentiated at the JVM level?

Inline methods in the JVM?

How are transactions implemented in MySQL?

What are the isolation levels? How does that work?

What is a transaction array? What does high water mean? What does low water mean?

Innodb index data structure? O, Lord

SQL statement execution process? What are the analyzer optimizer actuators?

Back to the table? Index push down?

What is the IOC initialization process?

Why SpringBoot?

Talk about autowiring?

Do you prefer MyBatis or JPA?

What are the implementations and differences between the two ORMs?

Ask the project…

Ask trainee…

How do you spend your time in college?

Do you find your college life fulfilling?

What are the common ways to learn?

Do you prefer b-side business or C-side business?

3.06 Financial Aspect 2 of New Retail Scenario 110 min (over)

To introduce myself

How are your grades in this major?

Have you ever failed a class? Why did you fail? Can you sum up this failing grade?

JVM memory model concepts?

What is your understanding of the method area/meta-space?

Allocation of memory in the heap?

Will persistent bands involve GC collection?

How do I monitor memory usage while the program is running?

How do I look at stack information when I run my program?

Java class loading process?

What is the magic number?

Why is it called parental delegation? Does that sound weird to you?

Can a private method that calls another class in one class be compiled?

Where does ClassNotFoundException occur?

Suppose there is now an executable for A.jar and b.jar, and they both refer to each other. Now that some classes in B.jar are gone, can A still start?

What do LDC,iconst,getstatic,ACC_FLAG mean?

What are the characteristics of IOC? What is your understanding of IOC?

We can implement IOC and AOP ourselves, and even pre – and post-processors, so why use what Spring provides?

How do I know that Spring’s IOC container is fully initialized?

What is the name of the interface for event subscription?

Why do I ask this question? Why do we need to know the initialization progress of the Spring IOC container?

What is the name of Spring’s post-processor interface?

The AOP and IOC integration process?

How does AOP do dynamic proxies?

How does CGLIB manipulate bytecode?

How does ASM manipulate bytecode?

Two parsing strategies for XML? What’s the difference?

Thread pool parameters?

What happens when a task is submitted to a thread pool?

Can you tell me about thread pools using the bank withdrawal example?

What is the bytecode for sync?

Sync lock what objects are static and non-static method locks?

Why is the object of the lock different?

Why use Maven?

A. Jar refers to c with version 1.0.0, and B. jar refers to C with version 2.0.0. A project relies on both A and B. Which version of C depends on? Why is that?

How many steps does a Maven arbitration policy have?

Transaction nature of database?

Differences in isolation levels? Why the difference?

What are the repeatable read and read commit isolation levels and implementation mechanisms?

What is “current reading “?

Why are caches used in projects?

Why is Redis so fast?

Redis persistence mechanism?

Can I continue writing while generating an RDB?

Why is AOF data falling disk before logging? And the database is to write a log and then down disk?

The sentry’s primary selection strategy? How does a sentry know about the presence of other sentries?

A HashMap eight-part essays

What are the characteristics of red-black trees?

Three handshakes and four waves?

Why does TIMEWAIT wait 2MSL?

What is the difference between 301 and 302 status codes?

Disk scheduling algorithms?

Operating system deadlock?

What’s the difference between a process and a thread?

Which type of IPC is the fastest?

How many states are threads in?

Process scheduling policy?

What’s the Angle between a 3:15 and a minute hand?

3.07 Service Center and Three sides 35min (over)

To introduce myself

Ask about projects, ask about internships

What was your role in the project?

What do you think of the atmosphere in TX?

What time do you usually leave?

Is there a lot of overtime?

In the RPC call process, we need to configure a service after the call timeout on the consumer side. How can we determine whether the call timeout has occurred?

How to set the timeout period?

How many times over are there? What would you do in a different situation?

What is the difference between 301 and 302 status codes?

The relationship between HTTP and RPC?

Where person? How do you study?

What do you think of b-side and C-side business?

conclusion

Finally decided to take the new retail scene of the financial process, Taobao shopping cart is still a big old board, nail nail poor written test and cross, business in Taiwan poor written test and cross, these interviews must enter the process to continue, the face is not moving, so the back about the interview are rejected. Let’s hope the interview after scene finance doesn’t go wrong…

The interviewer helped me to remember what I was doing in my freshman year and sophomore year. In particular, the interviewer asked me whether my college life was full or not

The last

Welcome to pay attention to the public number: the future has light, receive a line of large factory Java interview questions summary + the knowledge points learning thinking guide + a 300 page PDF document Java core knowledge points summary! These are some of the things that the interviewer should ask during the interview. These include basics, Java collections, JVMS, multi-threaded concurrency, Spring principles, microservices, Netty and RPC, Kafka, diaries, design patterns, Java algorithms, databases, Zookeeper, distributed caching, data structures, and more.