A staff of five years Java programmers swept BAT interview experience! Worth learning!

The entire spring trick lasted four months, on their own will is also a great challenge. I also had the opportunity to fight side by side with so many good people together, so I stick to the last minute, thank you.

This spring trick also encountered many strange companies, such as the US group I do not know why not to push inside, CVTE written brush internship experience, Gigabit hung somehow, Netease metaphysics recruit people, Jingdong 20 minutes interview, Huawei recruit chat people

Detailed interview process

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Alibaba

Side (36 minutes) Credit Sesame

1. hashmap and hashtable difference
2. Why deadlock
3. jvm class loader
4. acquiring private java reflection attribute, change the value of
5. Use reflection
6. Used database
7. Project difficulties, problems
8. How to solve the problems encountered in the project
9. Encountered in the project where they are most proud of
10. What algorithm

Two faces (44 minutes) Alipay innovation

1. Speaking project
2. Optimistic locking using a database
3. state machine
4. How to solve the problem not the state machine
5. How sub-library sub-table
6. MySQL limit
7. Source HashMap
8. Design a thread-safe HashMap
9. Fast row implementation, time complexity and space complexity
10. What algorithm
11. How the project turned into SOA architecture
12. Spring Source, the most profound module, aop use
13. JVM memory model
14. Garbage collection
15. View garbage collection project

On three sides (33 minutes) novice International

1. Project Rights Management
2. How to store login status
3. The difference between session and cookie, session on how to manage
4. HashMap substructure
5. Use of synchronized keyword
6. Lock difference synchronized modification class methods and conventional methods, but also to acquire the object lock after lock you get the class
7. The parent class loader delegate role model, you can repeat a class load
8. Cache class of class loader, what is the key
9. Introduction Redis
10. How data is distributed in different Redis
11. We have to take to find out about the algorithm?
12. spring realization of apo
13. Structure bytecode
14. Enter the URL the browser process, combined with springmvc

Four (36 minutes) novice international supply chain

1. HashMap hash collision in how to deal with a large number of
2. BST advantages than black tree
3. MySQL Why use B + tree
4. More indexes have multiple copies of data it
5. Isolation levels and solve database problems
6. Database default isolation level, will generate phantom read it, how to solve
7. Enter the URL to show the entire process, in terms of combined springmvc
8. Load balancing algorithm
9. Huffman encoding, decoding how to solve the problem
10. Internship work will affect you
11. English introduced a project
12. How to view the system load
13. Describe a process of problem-solving
14. How to copy files from the server to the local, what order

(27 minutes) five faces novice Technology

1. Baidu was how to find this opportunity
2. What technologies used in the project
3. How the project design process flow, if it is, then how can you design
4. MySQL uses the index structure to find efficiencies
5. MySQL query optimization
6. MySQL slow query open, statement analysis
7. Find HashMap efficiency
8. JVM memory model
9. Design patterns, strategies use scene mode
10. How to ensure singleton thread safety
11. The default scope of the bean Spring
12. Netty's understanding of the
13. Future development plans
14. How to make the code more complicated readability

Six (22 minutes) the HR plane

1. Talk about the direction of development
2. Talk about the problems caused by lack of experience
3. Talk about the content of the work of Challenge Cup
4. You talk about the main contribution to the project's Challenge Cup
5. internship period
6. What got the offer, consider how you are
7. Why not choose Tencent
8. Ali difference Tencent technology stack and technology stack

Tencent

Side (payment)

1. jqc Introduction
2. How to ensure the consumer will not be repeated multiple machines
3. How to ensure the consumer feedback failures (with transaction management, and then to store consumer, failed to rollback)
4. How to prevent the database from a single point of issue
5. paxos algorithm
6. raft algorithm
7. The spring aop achieve
8. Minimum number / 2 (only even number), i becomes 1 to find: - three operations, a:: ++, b, c
9. Personnel training (take turns trying to put forward the task, in the promotion)
10. No depth of breadth makes no sense, becomes a wide house, progressive approach
11. But empiricism requires experience dike design
12. Baidu atmosphere is better than Tencent Technology

Two faces

1. Multi-threaded code is handwritten tickets
2. Handwriting ServerSocket use code
3. How many java thread pool, thread pool is kind of fixed
4. The sub-interface Collection
5. Map interface, HashMap scenarios
6. Queue the parent interface, usage scenarios
7. Database master-slave replication configurations
8. Benefits of Spring IOC to solve the problem (decoupling)
9. Bean's life cycle
10. Bean of scope, gobal session of
11. Handwriting SpringMVC process
12. How to balance life and work
13. Career development planning
14. Why not PubMed
15. redirect and forward the difference
16. University biggest challenge
17. Encryption Algorithm

HR surface

1. I like to do
2. Like what movie to see, with what state of mind to see
3. Baidu will come back to you
4. What interview
5. What Tencent Ali choice, why choose Tencent
6. Only child
7. What people want to do at home

Today's headlines

Vibrato side

1. Shredded LFU, get and put requirements are O (1)
2. In a city ring, a thief can steal or not to steal choose any one, but not connected to the stolen house, find the greatest value

Side efficiency project

1. Water storage problem
2. How to find performance bottlenecks project
3. How many types of caches, from the client to the server
4. How to view system performance, performance indicators
5. redis data types
6. How much redis optimization of aof
7. From the master copy mysql
8. mysql engine, the difference
9. The process of establishing the link https
10. Whether the transmission data is the symmetric encryption https
11. tcp congestion control
12. and select epoll
13. How to deal with nginx connection
14. How do nginx performance optimization
15. apache and nginx difference
16. Two uneven fragrance, measured 15 minutes

Efficiency project two faces

1. Handwriting LRU
2. View the system load
3. Interprocess communication method
4. How to use the pipeline
5. socket setup process
6. How to efficiently handle socket
7. NIO principles and connection switching mode
8. What command view the system load, what is the first line
9. A table user_id, order_date, to check customer orders, orders for one day, one day a user orders, how to build an index
10. The composite index structure
11. The common data structures redis
12. Zset the underlying data structure, how to achieve a jump table
13. redis how to persist RDB

HR surface engineering efficiency

1. How to find an internship and internship Baidu
2. How to deal with their studies and internships
3. To talk about the project communication and collaboration process
4. How did you owner you is how to design the project
5. What got the offer, consider how

mushroom Street

one side

1. How Feng Ling rights management design
2. How 9s raised to 0.3s
3. With no search to find out about other frameworks such as solr
4. Coroutine have to find out about it? Where light
5. Command View gc jvm
6. How to solve the problem jvm
7. mysql in, not in, like do not go away Index
8. Development environment, development IDE
9. What command to view cpu and memory conditions
10. How to view the process of threading the case top -H -p
11. Spike scene design
12. When the spike limited resources if the machine how to do
13. You can ensure practice time
14. Planning for their future

Two faces (applet department)

1. Parents have no comment to Hangzhou
2. Consider it positive
3. The teacher or the students will evaluate how, how to reflect the technology is relatively strong
4. University proudest thing
5. A project to solve the problem
6. Nginx how to do overtime
7. mysql index-related
8. The principle% match
9. Www.baidu.com get the last point of the contents of "com" best practices, why, time complexity, how

HR surface

1. Deep introduce yourself
2. Relatively deep impact on a person you
3. What kind of person wants to be
4. The most rewarding thing
5. Recent setbacks
6. How bottlenecks
7. School and work environments What is the difference
8. Comparing the students around, what are the advantages

Jingdong

one side

1. Fast discharge principle
2. HashMap substructure
3. ConcurrentHashMap thread-safe principle
4. Class loading mechanism
5. The difference between the left and right connections
6. tcp establishing a connection
7. close wait time wait and under what circumstances arise
8. http composition
9. Http meaning head, keepalive of
10. https Process
11. How to ensure key security, whether asymmetric encryption
12. The principle of the thread pool

Two faces

1. What to learn in Baidu
2. Understanding of what java
3. They also learn other languages ​​too, just different preferences in different languages
4. aqs concrete realization
5. And those who use contract

HR surface

1. What to learn in Baidu
2. Why departure from Baidu
3. What are the advantages and disadvantages
4. The problem is encountered tend to solve the problem, issue or complain
5. How long can practice

NetEase mailbox

one side

1. java company
2. dfs and bfs principle and application scenarios
3. The realization of the underlying ArrayList
4. How Elastisearch index storage
5. JVM memory model
6. generational java heap, object allocation
7. Any problems in the project, as and solve
8. The project of their own to play a bit, why turn project
9. HashMao underlying implementation, introduced red-black tree
10. String a=“abc” String b=“a”+“bc” a==b?
11. How to meet the emergency needs of the completed
12. Handwritten ArrayList add 11 elements
13. n a number from 0 to 9, and to find the number of 7
14. MySQL engine, the use of the index structure
15. The difference between B and B + Tree Tree
16. Code optimization place
17. What usually see Forum
18. The principle difference from the JQC research, and the kafka
19. Grab a red envelope to achieve
20. How to transfer the password (asymmetric encryption, https)
21. https certificate issued in which

End surface (HR + charge)

1. How to find two practice
2. Practice it allows schools
3. Project Challenges
4. By a maximum difficulty learning to solve
5. Time how to handle the project, learning, internship
6. Why leave Baidu
7. Why not trust the boss, then you have a better choice

Netease game

1. How to ensure the expansion of the project, dependencies
2. Message Queuing at the same time consumption issues
3. The process of communication? Which most efficient
4. The machine socket unpacked stack to go through it
5. linux file management, file type
6. Achieve consistent hashing
7. Massive word frequency statistics up to 10 words, used data structures
8. Type strongly / weak type and static type / dynamic type
9. JVM class loader
   10. See machine performance
10. View cpu load, how much generally, how to solve too high
11. How is the performance of the machine readable

Interview feel

Spring trick is a very exciting and very grueling process, you may encounter various strange company, but only constantly enhance their strength, be more likely to get the Offer, Offer can not get a small partner do not be discouraged, after all, autumn is the highlight strokes, there is such a long time to prepare, I'm sure you also know that after the spring recruit what areas are relatively weak.

In this small series to share sorted out for the interview portion of the interview BAT answer, we need to get friends can add about Qqun: 963944895free access.

While also finishing a set of reliable knowledge learning map, hoping gains ideal Offfer help you move in the autumn .

" For programmers, if one day he began to stop learning, then his career began to be pronounced dead ." This is not alarmist strange language, but a few years ago, Daniel told me.

In recent years, because the programmer salary climbing higher and higher, leading people in the IT industry, more and more, but also to indirect business requirements for developers are also increasing. Learn to what extent say that they are eligible to be proficient in Java? At least personally I feel the need to do the following:

1. The importance of code quality

Importance of code quality, excellence, which is the essence of technology development, as well as a foothold in this programmer .

Of people in work or not work around this stage of the year, the reading is a better way to enhance recommend "Java programming ideas", "effective java" and so on. Note that, in the process of reading a certain book to think about whether to use the experience to improve their own code to write, use into practice, you see that final and static, think about using their code is reasonable.

In addition, you can also see some popular open-source framework, if you are using the Spring framework, etc., then the following knowledge map can learn:

2. Expanding horizons technology

After laying the foundation initiative out of the comfort zone, expanding their technology horizons .

This step is more difficult, because many people will be carried away by the company's technology and business. For example, the company's current business scale determines the technology does not require a distributed technology, a lot of people would not have to think about how to use after large-scale distributed technology to solve the problem.

这种时候，除了寻找更大规模的业务外，要时刻保持跳出当前层级和环境来思考的习惯。比如，你只用了关系型数据库，有没有想过数据一直产生，到达TB级别的时候该如何快速检索与保存呢？

3. 微服务架构

微服务是现在互联网架构技术中最火热的话题之一，也是小编目前正在学习研究的方向。在阿里面试过程中，面试官很少会问到关于微服务相关的问题。但作为一名开发者，一名有技术梦想的程序员微服务架构是现在必须要去了解的主流技术，小编给自己制定了一个微服务技术的学习计划：

4. 并发编程

并发编程几乎是所有互联网公司面试必问问题，并发编程是Java程序员最重要的技能之一，也是最难掌握的一种技能。它要求编程者对计算机最底层的运作原理有深刻的理解，同时要求编程者逻辑清晰、思维缜密，这样才能写出高效、安全、可靠的多线程并发程序。目前网上没有系统的全面的并发编程学习图谱，我搜集了很多资料总结出来一个最全面的学习图谱：

5. 性能优化

性能一直是让程序员比较头疼的问题。当系统架构变得复杂而庞大之后，性能方面就会下降，特别是阿里巴巴这样的一线互联网公司最为注重，因此想进入阿里，性能优化一定是要去深入学习与理解的一环，本屌在性能优化这一块虽然不能算专家，也可以自信的说是精通了。

6. 设计模式

设计模式（Design pattern）是一套被反复使用、多数人知晓的、经过分类编目的、代码设计经验的总结。使用设计模式是为了可重用代码、让代码更容易被他人理解、保证代码可靠性。 毫无疑问，设计模式于己于他人于系统都是多赢的，设计模式使代码编制真正工程化，设计模式是软件工程的基石，如同大厦的一块块砖石一样。项目中合理的运用设计模式可以完美的解决很多问题，每种模式在现在中都有相应的原理来与之对应，每一个模式描述了一个在我们周围不断重复发生的问题，以及该问题的核心解决方案，这也是它能被广泛应用的原因。

7. 底层知识

从架构设计，到应用层调优，再深入了解底层原理，扎实的Java基本功才能让自己变为扫地神僧：

• 内存模型
• 并发模式
• 线程模型
• 锁细节

以上七大知识体系是我从业多年总结出来的经验，都是当前最主流的技术，技术的突破需要依赖业务场景的需求和自身刻意的规划学习，二者缺一不可。但前者是机会，往往不是自己能完全把控的，如果在工作中没有实践场景，最好的办法就是系统的学习与梳理，待机会来临时才能一展身手。如果对Java分布式、工程化、高并发、微服务，JVM等技术感兴趣的可以加Qqun：963944895免费获取已整理好的部分学习资料。