Ali's face to record electrical experience, especially to share with you, the post is JAVA R & D engineers.
Side of the main issues are as follows:
1) First, mij
basic problem 2) data structure algorithm, such as the sorting algorithm, the binary tree traversal, non-recursive postorder traversal, the shortest path problem FIG.
3) of the absolute value of a sorted array algorithm
4) java hashmap in the underlying realization
5) java garbage collection mechanism GC principles, etc.
6) introduce their projects, the data structure of the data used in the model database, the concept of deadlock (deadlock should be asked of the database), how to avoid a deadlock?
7) optimistic and pessimistic locking?
8) consistency hash algorithm
association of business objects 9) project / associatively, left outer join and talk about how many relationship model 10) spring of IOC and AOP
how 11) sping achieve (ensure) the integrity of transactional consistency, spring type of transaction propagation mechanism
12) to talk about WEB architecture (should refer to the j2ee development framework model), user scenarios project usage scenarios 13) understanding of the distributed architecture, such as distributed storage distributed cache distributed computing
14) to talk about an understanding of what open source projects Ali?
15) Is there a technical understanding of Taobao?
16) of its Hangzhou Information Platform Division, its main business to know whether (which is the development of java aspects, look the other can focus on workflow engine)
two faces major problems as follows:
1) First of all is still to introduce themselves
2) had competition experience? Awards? Rankings? Usually have to see what books? Whether to participate in the school community activities? Which department? The main work? Schedule?
3) Which technologies are most familiar is best at? I'm talking about those java WEB framework, and then began to ask the java
difference 4) implementation of interfaces and abstract classes What are the differences?
5) how to serialize achieve? Described by the code. writeObject? objectWrite? ObjectOutputStream.writeObject (). ObjectInputStream.readObject ()
Description IO framework Collections Framework 6). How to determine if a file exists? How to read a directory of all files and subdirectories? Code Description.
7) breadth-first traversal of all the subdirectories and files in the directory below? Code? List and Map different? HashMap implementation? How to resolve hash collision?
8) multi-threading mechanism? Thread sleep 10 seconds? the difference between sleep () and wait () is.
9) Use buffered stream buffer of? principle?
10) How to view usage under linux CPU load and IO ports? How to create a table of contents? How to search for a specific character?
Sql 11) examine the operation of the database, given a specific business table, statistics for how different types of data.
12) the concept of affairs? Dirty read? How to avoid? How to achieve in the code?
13) sql code, how to how to define a transaction? It is how to define a transaction isolation level?
Question 14) encountered in the project? Solution?
15) SSI frame? How to define a spring bean? code descriptions. Bean's life cycle? Bean of scope? 16) knowledge of Taobao technical architecture? Where to get? Their future career plans? Technology development? 17) Finally, the intention of Hangzhou and Ali to work? Then I asked myself what he would like to ask? Talk about the main business information platform for the next division? Workflow and ERP?
Overall, it is quite particular focus on basic multithreading and concurrency safety and related java database, in addition to the specific underlying open-source framework concerning implementation requires more than reading the source code and summarized.
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1 hashmap, hashtable difference.
2 whether to find out about hashmap source?
3 jvm related mainly memory allocation process, when starting GC, to monitor what tools or commands?
Class 4 loading, type isolation mechanism.
5 spring of ioc, aop, things, then things mentioned in passing database, two-phase commit, database lock level, MySQL database lock is special (page-level locking)
6 the Java thread pool inside arrayblockingqueue, linkedblockingqueue use and the difference.
7 design patterns related, mainly on the use of
8 How to ensure the uniqueness of the database cluster ID, assuming concurrent 200,000 times per second.
9 concurrency level of one hundred thousand website design background, how to calculate the number of ecs use (cloud server (Elastic Compute Service, ECS as Ali ECS) is an elastically scalable processing power of computing servers, based on optimal routing algorithm framework BGP multi-line network, the cloud server can help build a more secure and stable applications).
It uses the similarities and differences of 10 memcached and redis.
11 nosql database-related, mainly about mongodb
an integer of 12 10G, the largest one removed (not just using an efficient sorting algorithm, but also need to consider the memory size)
13 is the synchronized, volatile, and the use of reentrant lock disadvantages.
14 java api basic understanding and application of relevant core nio
15 consistency hash
16 which there is a single point of failure in a large system of
17 hadoop optimization related
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Side, the main focus on basic, asked a very deep wide stress interview.
1.hashmap, concurrenthashmap underlying implementation and the difference
principle 2.spring framework
3. How to write a orm framework
4.hibernate cache and secondary cache, hibernate other cache
propagation behavior 5.hibernate Affairs species
6.springmvc principle
7.restful benefits
8.restful several requests, how to put a form to submit a request
to consider security issues in 9.web, how to prevent
10.web overall system architecture
how 11.hibernate implement declarative transaction
12.java and contract
13.volatile
14 . usually have to see what books
15.spring underlying data structure
16. how reflection, reflection on how to improve the performance of
the proxy 17. how to achieve java, why the need to implement the interface
18.TCP three-way handshake protocol
19.springmvc which notes used
20. springAOP which agents can use, what is the difference
21. Why three layers
22.mybatis and hibernate What is the difference, why not write directly to hibernate sql statement? This surface is not ready, a great breadth and depth of pressure, suggest that you take a look at the three major source framework, principles, and contracting.
Second interview focused on projects
1. What is restful web service?
2. Concurrent collections package?
Which are used in the data structure 3. Project?
4.TCP disconnected four wave?
5.MD5 salt
6.https
7. Alipay interface development
8. know what lock, what's the difference?
9. still JDK source
10. The project encountered any problems, how to solve?
11.JDK1.8 What's new?
Perhaps that one side has been asked a lot, but this side answer was quite good, in 20 minutes, and 30 minutes the results.
Life on three sides talk
leader people very nice, gave some advice that might be about the same technology, and basically did not how to ask this technology, mainly professional development, IBM's practice content and the like, I think we might have their own ideas, 18 minutes.
hr face chat upbringing: B2B chatted understanding of the technology and its own growth process.
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Point Like Me: private letter reply "data" to obtain high-level architecture of Java data, source code, notes, video
Dubbo, Redis, design patterns, Netty, zookeeper, Spring cloud, distributed,
High concurrency architecture technology
1.Java basis
Processing ArrayList, HashMap and other collections framework classes, such as String class an important foundation. HashMap underlying storage structure.
(Incidentally, you can also under investigation for interfaces, inheritance, overloading a basic understanding of rewriting; and notes exception handling).
- Data Structures and Algorithms
Common search algorithms and time complexity.
Common sorting algorithms and time complexity.
Important data structures, such as a basic understanding of linked lists, queues, and the stack is substantially achieved.
- Multithreading
1) thread-safety issues. Are HashMap thread-safe, why not safe. ConcurrentHashMap, thread-safe, why security. It is kind of how the underlying implementation.
2) use a common class under the JUC. ThreadPool in-depth study; use of BlockingQueue. (Take, the distinction poll, put, the difference between the offer); atomicity class.
3) the use of a variety of common locks
If the above good grasp of these, you can also take a look a little deeper False Sharing, Cache Line, visibility and atomicity and so on;
- JVM
Java Memory generational model, GC algorithm, JVM common startup parameters; CMS process algorithm.
Answer this better, you can also just look Bixuan of Java distributed development or articles online learning can be combined with JVM startup parameters for common configuration, jstat commands, look ability, willingness; and the actual online troubleshooting.
5.Linux use to troubleshoot and problem analysis
. 1) grep, awk, sed; whether he wrote a shell script;
2). Common cpu load too, us too, generally what the problem is. Extended whether used top, jstat, jstack and so on.
Common memory problems usually what. Extended whether used free, top, jmap and so on.
- The framework uses
Principle spring aop bottom. aop and cglib, relations with the asm.
spriong ioc life cycle, (init-method, intilizingbean afterPropertiesSet the order interface method) and the like.
Hibernate use of the twelve cache, Lazy-Load understanding;
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Database Related:
- mysql storage engine indexing mechanism implemented;
2. Several granularity of database transactions;
3. row locks, table locks; optimistic locking, pessimistic locking
8. Network Protocol:
HTTP protocol;
HTTPS protocol, SSL protocol and complete interaction;
- repeat
redis, memcache client uses a consistent underlying Hash, to see if understanding;
redis event-driven multiplexing underlying implementation; NIO to extended program, look for Netty, whether or mina understanding.
If the candidates at the same time used memcache, redis, look at the difference between the two to know whether the use of scenarios. To examine the depth of use, and whether there are curious spirit.
- Design Patterns and Reconstruction
Common design patterns, such as singlen, factory, abstract factory, strategy, chain, adaptor, decorator, composite, template, absever and so on.
Reconstruction: Reconstruction of books
- Learning initiative
What technology has recently been to the site; which books recently watching.
- Compression capability and willingness to compression
Learn overtime, willing to know whether a period of time such as 996;
13 Stability
Learn family marital status, understand the purchase and place of residence, place of origin, the understanding of the current salary, assess stability;
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1. The difference between processes and threads
2. What is thread-safe? Illustration
3.OSI seven models, including some TCP, IP basics
lock 4. database
5.DFS, BFS algorithm
6. There are some, such as the Java collection framework base
7, http, the differences get post of
others interview, feeling very representative asked:
The first surface (just remember so much)
1, pen and oral questions to achieve a fourth title under
2, there is a 5k requests per second, the query document questions the phone number belongs to (remember incomplete, not listed), how to design algorithms? Request more, such as 5w, how to design the whole system?
3, more familiar with what technology? I say jvm and oracle, let me draw architecture jvm, saying responsibilities of each part after painting, wander and runtime optimization.
The second surface (not the technical details, are generalities, but I answered the more conservative, and could feel the rattle can dare say a half hour, said read or learn)
1, are you willing to go to Hangzhou
2, familiar with the various technical framework for it? Source read it?
3. What database understand? Mysql understand what
4, the front desk, watching ExtJS I use, and asked if he understood JQuery
5, enter now The company, that has been raised on whether the technology?
third face, this face no technical problems
The fourth plane HR (feel this face to answer lame, after all, so many years for the first time face HR, in front of over two or three companies, either hung up very early, or feel the process is too long, I do not want to go face )
1, Hangzhou willing to develop it? I said we should consider, hr asked to consider what the main issue 2, from a technical point of view, do you think you and your classmates than 3 how about your parents how you look at the 1, jvm performance tuning have done what
2, high concurrency, our system is how to support a large number of requests
3, how to synchronize the cluster session state
4, load balancing principle
5, database transaction properties
6, binary tree traversal algorithm
7, the difference hashtable and hashmap
8, concurrency, synchronization interfaces or methods
9、string、stringbuilder、stringbuffer区别
10, a processing procedure https, symmetric encryption and asymmetric encryption
Several state 11, thread
12, to understand what mobile developers
13, personal strengths
14, when communicating with colleagues, how to resolve the conflict if it is
15. Which aspects of the work that lack?
16, there are questions to ask it?
17, salary expectations
18, why did you leave the company now distinguish struts1.2 and webwork of the difference between hibernate and ibatis the spring mechanism, IOC container of some issues related to the servlet webservice related java foundation: jvm, HashSet, etc. * Ability to learn new techniques of investigation
other:
- Shop related business characteristics of the decision, there are front and rear end of knowledge is a plus items. If the candidates are familiar with javascript.
You can visit:
1) front and rear ends basics optimization, such as on the back js not obstruction; native js understood, is the time bubbling like.
2) firebug, fiddle and other debugging tools;
3) If it is essential to use, look ext framework, familiarity with jquery and so on. jquery plug-in mechanism, sizzle selector.
If the above are good, we can go any further investigation
1) scope chain, understood that closures.
2) whether the look for the latest technology. augularJS, nodejs, cmd specification, amd norms.
Ali faces issues related to HR shared as follows:
1. Why did you choose this sector? In an open question because the school recruit personal information, there is a question: What are you most expect Alibaba internship department or project? Please know your next presentation of the sector and the reasons for hope internship? And I just wrote a department name, not expanded explanation, so hr have this question.
2, has participated in other companies before hiring you? Why did not pass?
3, Ali internship recruitment reason for the decline? What the problem is not a good answer? The question whether the summary yourself down?
4, the impression Ali's classmates or evaluation?
5, to participate in extracurricular activities? Community? In addition to learning, there are other events?
6. Why did you choose to graduate school? Different graduate and undergraduate? The biggest difference graduate school after that?
7, asked if any internship or work experience how to treat? You can advance to do an internship?
8, there had been feeling frustrated own thing? Talk. Recently I encountered the most difficult thing?
9. Why did you choose to work in Hangzhou?
10, the end of the interpolation process this week, before the August 15 notice results. Finally, you ask whether so what? Hr overall feeling is still very good attitude, communicate with each other quite easily.
The main use of the technology stack Summary:
Fanger Wei code scan: search or Q group number: 739 486 042
Click on the link to join a group chat [java architecture study group]: https://jq.qq.com/?_wv=1027&k=5G1eNmB
Architects build the base topic: 
open source analytic framework topics:
High-performance architecture topics:
Micro-service architecture topics:
Teamwork development topics:
B2C project combat:
Concurrent programming topics:
