Interviews with Meituan, Toutiao, Baidu, Jingdong, an interview summary with 3 years of Java development experience

Preface

I have learned a lot since I graduated and switched to development for 3 years, and coupled with my hobbies, I personally think that I have become a qualified programmer.

The same as the first job interview is that they will ask the same questions. The difference is that now interviewers will pay more attention to why, that is to say, focus on depth rather than breadth. 3 years, 5 years, and 10 years are personally engaged in technical aspects. A hurdle in career planning, most of the 3 years have dealt with business logic, cultivated good norms and ideas, but the basic knowledge is still lacking.

When looking for a job, it is also very important that the salary is in line with the personal career plan. To speak less nonsense, the following are the interview questions I summarized in the interview two days ago.

JavaSE

set

Hashmap structure and principle

Expansion factor, how to expand, data structure diagram...

ArrayList, LinkedList principle and difference (draw the data structure)

The four elements of the collection: whether it can be repeated, whether null values ​​are allowed, whether it is ordered, whether it is thread-safe...

Thread-safe collection, why map is thread-safe, and which operations are related to thread-safety

algorithm

Talk about a few common sorting algorithms, implementation principles, corresponding time and space complexity, stability

Hand tear an algorithm (writing): You can choose to bubbling

Recursive algorithm

Object-oriented

Polymorphism

Object-oriented features

static usage

The difference between String and StringBuilder, when to use'+'. It is best to answer the realization principle of'+' after javap compilation

Multithreading

How the thread is implemented

Thread status

Common thread pool and usage

The realization of the end of one thread and the start of another thread

Thread principle (ThreadLocal)

The difference between start and run

Pessimistic lock optimistic lock

IO style

Write a read-write file

Affairs related

Transaction mechanism

AB is a transaction, C has A, B, if A or B fails in C, what is the state of rollback C

What is business and usage scenarios

Frame related

Spring , MVC, MyBatis

Introduce Spring and its commonly used annotations, Spring IOC implementation principles, AOP implementation principles and usage scenarios, and dependency injection principles

Spring transaction propagation and isolation level

MyBatis mapping principle

Distributed related architecture

System architecture introduction, architecture design diagram and what architecture is used in what scene

Dubbo mechanism, Zookeeper mechanism and their relationship

Redis data types and usage scenarios, refresh interval

Kafka introduction and the role assumed by the usage scenario

Tell me about Storm

database

MySQl

MySQL database storage types and their advantages and disadvantages

Distributed sharding and database design, master-slave structure

other

sql optimization

Index creation principle (hand write a SQL)

SQL centralized DDL, DMl==

Rules or precautions for table building

Database isolation level and reasons

Design Patterns

Introduce common design patterns and usage scenarios

Write a singleton pattern implementation

communication

HTTP related introduction, the difference between GET and POST

JVM related

Java garbage collection mechanism

Java memory structure (related to the recycling mechanism)

other

RBAC permission model, distributed Session implementation

Common linux commands (how to view the 200th line of the file, how to find the file)

Written at the end, I met four companies in two days and had 3 offers, among which JD.com’s did not. To sum up, JD.com, a technology-driven company on the Internet, pays more attention to personal basic knowledge, self-learning ability and hands-on ability. They I can ask very detailed questions and I am unprepared. It is quite difficult to deal with it. It is normal that I have never had it.. Because I asked for leave and interviews to check the market first, I was not prepared. Many things were not answered well, but due to my experience in general companies. I agree, but in this case, the salary will not be ideal, so I suggest you prepare more.

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Interview Collection

• 115+120 Internet interview questions and answers
• Ant Financial Interview Collection
• Dubbo interview questions and answers
• Java back-end interview questions and answers
• Java experience
• JVM interview questions and answers

 

(1) Java Interview Manual

• Performance optimization interview column
• Microservice Architecture Interview Column
• Concurrent Programming Advanced Interview Column
• Open source framework interview questions column
• Distributed interview column

 

(2) Actual documentation

• Redis combat
• MySQL combat
• Spring Boot combat
• Spring Cloud combat
• Actual Java Virtual Machine

Take the actual combat Java virtual machine as an example:

1. Probe into the Java Virtual Machine
2. Understand the basic structure of the Java virtual machine
3. Common Java virtual machine parameters
4. Garbage collection concepts and algorithms
5. Garbage collector and memory allocation
6. Performance monitoring tools
7. Analyze the Java heap
8. Locking and concurrency
9. Class file structure
10. Class loading system
11. Bytecode execution

 

(3) Java core knowledge points to organize documents

 

 

Due to space limitations, many contents only show catalogs and screenshots, which are organized in documents. Those who need these documents can be shared with everyone for free . I hope all programmers can learn and strive to achieve our big factory. dream!

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