Bytedance was bumpy all the way but got an offer, my interview experience sharing (Java R&D)

Foreword:

The beginning of this year is somewhat special. The epidemic has had a great impact on our lives. For a job seeker, it has added a "difficult wall". Despite this, we cannot miss out on money. Three silvers and four opportunities should be seized. Nowadays, many Internet companies have adopted the method of online interviews, so prepare in advance, submit your resume and interview smoothly, and you will surely win the offer you like. And I finally get the success I want. ByteDance succeeds in 4 ways. Clearance.

 

Personal introduction:

I was born in a small town in Jiangnan and studied in Beijing. I stayed there after graduation. I have a 211 undergraduate degree. I have good qualifications in all aspects. Therefore, my own advantages can be fully reflected in my resume. Many companies have thrown an olive branch. As long as the interview goes well, it is basically the company's choice.

The following mainly share experience and personal learning methods, which will include many PDF documents, such as interview question bank (including answers + analysis), study notes, practical documents and brain maps, etc., which can be shared for free

ByteDance 4 core interview questions

01 Zookeeper section

• CAP theorem

• ZAB agreement

• Leader election algorithm and process

02 Redis section

• Application scenarios of Redis

• Data types supported by Redis (required)

• The data structure of zset jump table (required)

• Redis data expiration strategy (required)

• The specific implementation of Redis's LRU expiration strategy

• How to solve the Redis cache avalanche and cache penetration problems

• Redis's persistence mechanism (required)

• Redis pipeline

03 Mysql section

• Basic elements of business

• Transaction isolation level

• How to solve the problem of transaction concurrency (dirty read, phantom read)?

• MVCC multi-version concurrency control?

• What are binlog, redolog, and undolog, and what are their functions?

• InnoDB row lock/table lock?

• The difference between myisam and innodb, when to choose myisam?

• Why choose B+ tree as the index structure?

• What can be stored in the leaf nodes of the index B+ tree?

• When will the query not go to the (expected) index?

• How to optimize sql?

• How does explain parse sql?

• Principle of order by

04 JVM part

• Runtime data area (memory model)

• Garbage collection mechanism

• Garbage collection algorithm

• Minor GC and Full GC trigger conditions

• GC中Stop the world

• The characteristics and differences of each garbage collector

• Parent Delegation Model

• Relationship between JDBC and Parental Delegation Model

05 Java basic part

• The difference between HashMap and ConcurrentHashMap

• Data structure of ConcurrentHashMap

• How does the high-concurrency HashMap ring come into being?

• Volatile role

• How to ensure atomicity of Atomic class (CAS operation)

• The difference between synchronized and Lock

• Why use thread pool?

• Parameters of the core thread pool ThreadPoolExecutor

• ThreadPoolExecutor workflow

• How to control the priority of thread pool threads

• How to communicate between threads

• Boolean takes up a few bytes

• What new features are added in jdk1.8/jdk1.7?

• Exception和Error

06 Spring section

• Implementation of Spring's IOC/AOP

• Implementation of dynamic proxy

• How does Spring solve circular dependencies (three-level cache)

• Spring's post processor

• How is Spring @Transactional implemented?

• Spring's transaction propagation level

• The connection and difference between BeanFactory and ApplicationContext

07 Network Programming

• TCP connection and disconnection process?

• The interaction process of HTTP protocol•The difference between HTTP and HTTPS, and the interaction process of SSL?

• What is the use of TCP's sliding window protocol?

• What are the methods of HTTP protocol?

• The basic process of Socket interaction?

• Talk about the tcp protocol (connection establishment process, slow start, sliding window, seven-layer model)?

• Webservice protocol (wsdl/soap format, the difference with restt protocol)?

• Talk about the Netty threading model, what is zero copy?

• TCP handshake three times, wave four times?

• DNS resolution process?

• How does TCP ensure reliable data transmission?

08 Distributed

• What is the CAP theorem?

• Talk about CAP theory and BASE theory?

• What is final consistency? How to achieve final consistency?

• What is a consistent hash?

• Talk about distributed transactions?

• How to implement distributed locks?

• How to implement distributed session?

• How to ensure the consistency of the message?

• Understanding of load balancing?

• Forward proxy and reverse proxy?

• How does CDN work?

• How to improve the QPS and throughput of the system?

• The underlying realization principle and mechanism of Dubbo?

• Describe the detailed process of a service from being published to being consumed?

• How does the distributed system do service governance?

• How does the message middleware solve the problem of message loss?

• How to deal with the failure of Dubbo's service request?

09 Other parts

• How to realize the current limit of high concurrent system?

• The design of high concurrency spike system

• How to design load balancing?

Answers to ByteDance interview questions:

Due to space issues, the answers to the interview questions are organized in a pdf file. If you need the answers to the interview questions, you can get them for free through private message [Interview]~

 

What preparations did I make for the ByteDance interview?

(1) Adjust your mentality and face gains and losses correctly

The most common problems in interviews are mentality. Interview adjustment mentality comes first. How to adjust to the best mentality? During the interview, many job applicants have unclear thinking, unfluent language, illogical speech, and will continue to deny themselves. In the final analysis, it is a question of interview mentality. Therefore, it is very important to adjust their mentality and face gains and losses correctly. The method is to give yourself enough psychological hints.

 

(2) Improve technology and broaden knowledge

For programmers, if they want to grow into an industry leader, the only way is to continuously improve their skills, broaden their knowledge, and reach a certain height and depth through learning. So how do you improve your technology and expand your knowledge reserve?

The following are some of my personal practices, I hope I can provide you with some help:

283 page pdf document

Java part: Java foundation, collection, concurrency, multithreading, JVM, design pattern Data structure algorithm: Java algorithm, data structure Open source framework part: Spring, MyBatis, MVC, netty, tomcat distributed part: architecture design, Redis cache, Zookeeper , Kafka, RabbitMQ, load balancing and other microservices : SpringBoot, SpringCloud, Dubbo, Docker

 

 

(3) Rewriting questions

How to write questions? This is the confusion in the minds of many interviewees now. We all know that it is necessary to brush questions before the interview. After all, many questions have certain commonalities. If you brush enough questions, you can draw inferences from one another, and even get asked during the interview. The original question can be talked eloquently, so how to proceed with the question? Suggestion: It is best to find some original interview questions over the years and train yourself by topic.

The following is my private interview question bank:

 

Reader benefits

The last point I want to emphasize for interviews with large factories is that the mentality is really important, and it is the key to determining your performance in the interview process. If you can’t perform normally, it’s likely that you missed the offer because of a small mistake, so you must pay attention to it. stand up. Another reminder, full review is the key to eliminating your nervous state of mind, but if you review enough, you will naturally have more confidence in the interview process.

All the learning materials and interview materials in the above content can be provided free of charge. I hope that everyone will have a smooth interview and win your favorite offer!