Tencent face by Java

User 1

Author: xjia
link: https://www.nowcoder.com/discuss/225392
Source: Cattle-off network

The basic structure of 1.jvm

2. The memory partition

3. VM stack exception type and reproducibility Code

4. heap memory exception type and reproduced

5. how to use Direct Memory and its management jvm

6. Concurrent container species

7.concurrenthashmap data structure

8. When the list becomes red-black tree and back to the list

9.mysql know several data engine

10.innodb and mylsam difference

11. Failure Index

12. The covering index

13. What is the value of three-way handshake is ack

14. The resulting deadlock how

15. how to prevent deadlock

16. Deadlock code demo

The difference 17.arraylist and linkedlist

Why 18.arraylist query fast (ps addition to the random access Why else)

19.io know of several types

20.nio is one which

 

User 2

 

Author: Wow it's Uncle
link: https://www.nowcoder.com/discuss/225485
Source: Cattle-off network

1. Under what to do about the internship: a little.

2. Java final keyword: slightly.

3. Java reflection characteristics: any configuration object runtime execution method.

4. Communication between processes: object of wait, notify; ReentranLock; CountDownLatch; CyclicBarrier.

The deadlock conditions of: exclusive, inalienable, and holding request, wait cycles.

6. deadlock will result in an infinite loop and the program hung to live, how to judge a deadlock or infinite loop: find a corresponding pid began with jps, then jstack pid, view the process in the state of the thread, then there is no deadlock analysis the interviewer said ok, there are no other practice, I can say that the cycle of death interrupted the deadlock can not be interrupted (may be wrong), the interviewer said ok, there is no system to judge the state by the way, I, cpu.

7. The significance of the thread pool parameters: Investigation maximum number of threads, the core number of threads, waiting queue, refused strategies.

8. Oral algorithm: two-way linked list, find the point of intersection.

9. Oral algorithm: mutation decimal binary switch,

1 can turn 001

2 can be transferred 010,002

3 can turn 011

4 can be transferred 100,020,012

Q. 10 How many n-ary conversion method.

The interviewer introduced under their department, the use of language

What do you want to ask.

Tencent feel like to ask dp ah, two rounds of interviews met three dp algorithm.

 

User 3

Author: KL3
link: https://www.nowcoder.com/discuss/219646?type=2&order=0&pos=4&page=1
Source: Cattle-off network

Operating System  Memory section (virtual address how to find the physical address)
swap partition
Why virtual address
how to view the situation linux memory
stack process which put what

Fast row   merge sort
Oral algorithm  longest palindromic substring
three-way handshake
syn attack
polymorphic
hashmap hashtable
thread state (blocked Waiting TIMED_WAITING)
the JVM memory allocation
== equals hashcode
database isolation level
Dirty read   Magic Reading

 

Two over all things: Duration 22 minutes

Feel the interviewer is not engaged in Java, many issues are voiced by myself, we are talking about understanding.

Talk about the understanding of concurrent

synchronized 和  lock

Talk about juc tools you know

Problems climbing stairs

mysql connection object problem
long transaction
MVCC
Change Buffer
Project

You are undergraduate and graduate

Would you like to do in Chengdu

Doing internships

 

Three sides

At 10:00 on August 13 34 minutes

Say under what framework you use

Talk to understand and spring cloud of spring mvc

You are practiced serialization framework dubbo of use protobuf it

Talk about tcp and udp

tcp的time wait 和 close wait

Talk about congestion control

How to control the size of the sliding window

(There is a sliding window problem, some can not remember, then did not answer on, not to say, afraid to mislead everyone)

If the server has entered the close state, the client is still in the time wait state, occupied the port, how to solve

View the number of commands tcp connection

You know what linux command

linux in '|' What is the role?

 

The current system performance bottlenecks encountered, how to locate the problem

How locate memory leaks

Tell me about your tuning direction of jvm

Talk about jvm gc features, your understanding

 

You do in school project to harvest what you

The size of the project, the number of users and the like. . .

User 4

Author: stay up all night is the root of all evil
Links: https://www.nowcoder.com/discuss/224096?type=2&order=0&pos=6&page=1
Source: Cattle-off network

one side

• MySQL Index
• MySQL Innodb engine of affairs is kind of how? (ACID) MVCC? Lock?
• MySQL master-slave replication principle
• The difference between a primary key and unique index pairs
• There MySQL Replication it? Semisynchronous it? (First asked, learned)
• MyISAM storage engine under the table and index data are stored in what way?
• When joint index will not be used?
• b + tree to talk about
• 100 nodes of how binary search tree to find his first 80 big node
• If the master node Redis cold how to do? Note Sentinel and cluster model is not the same
• Redis fragmentation principle, hash algorithm which is used?
• Redis a client node can access other fragments of it
• Redis master-slave replication principle
• If Redis master copy off from midway how to do? How to solve? If it has been broken for a long time? Half-way cut off by re-take the data buffer memory on the master node, the size is 1M, if the data over, you can not recover
• Spring MVC process is kind of how?
• Related front end: React parent component subassemblies how to pass the Senate? React and JQuery difference? What function is the arrow?
• linux command to see what load? I see a certain port is not occupied with what order? What linux command to establish hierarchical directory?
• Talk about tcp three-way handshake
• Talk about https handshake
• Shredded Code : Given a string, to find the longest string palindromic

Two faces

• Practice what to do?
• As a developer you think there is any way to help the operation and maintenance?
• Talk about the difference between Java and PHP
• If there is a large amount of concurrent requests a read request our database, you should think how to squeeze performance of the database?
• If there is a large amount of concurrent write requests request our database, what do you think should press database?
• Known Node A ping B node when the length of 30ms, ask wget B Node A node resource, the resource will be able to send a package by default, how long?
• Do you know how to debug break it? I ask if a server is already running, and how we as in the development environment to its break point.
• How to monitor our business information, such as how much volume of transactions per hour, not to invade change business code, give a thought?
• If you go to find a load linux server, how to find you.
• You say the database connection pool, if we do not want to compare the database connection pool and connection pool with the database, how do you go to find their response time difference? Not from the operational level, from a more basic level, to analyze the database
• If a person tells you that you are the web interface is slow to respond, your investigation is kind of how?
• Our business there are many queries to the database, if you want to count how many times each query needs are? What would you do? Without a splicing a SQL statement it (too many SQL statements), how would you do?
• If you have a springboard machine, how are you to verify that it is working properly? Talk about your ideas?
• If node A to node B call service, and A node that is Node B process is too slow, and they say Node B processing speed is no problem, you should how to troubleshoot the problem? You can not change the code, go up the investigation on the existing foundation?
• Do you think you can develop the operation and maintenance of what is automated to help develop?
• We know the code to compile C is very troublesome, very often our development efficiency will be affected, and many of our business is written in C, if we publish business with docker, if it is you, what do you think now will be able to alleviate this situation?
• You know the deal with this kind of way ELK log, you can tell me some dimensions from which we can go to find the information we want it?

User 5

Author: Wow it's Uncle
link: https://www.nowcoder.com/discuss/223656?type=2&order=0&pos=7&page=1
Source: Cattle-off network

1. Self-introduction internship experience

2. What language is used? Java? There are other familiar languages? C?

3.C pointer is the physical address?

4. The difference between the stack and heap

The difference 5.hashMap and hashTable

The arithmetic without seeking a number of times 7

6.AB two files have 5 billion url, each url 64K, how to find the same url

710 000 000 Number demand topk

8. There are two incense, incense uneven burn completely to each one hour, 15 minutes determines how seek

9. For the 12 floors, each floor has a diamond, large and small, lift from the bottom up, you can open the elevator doors on each floor view, but can only take one, and can not be exchanged, is there any way to get to the largest

10. The two eggs, floor 100, it is determined that the critical layers of eggs will break

What do you want to ask

====================================

emm Well, I just received Tencent written test, interview possible before cold

User 6

 

Author: Star 007 007
links: https://www.nowcoder.com/discuss/222766?type=2&order=0&pos=10&page=1
Source: Cattle-off network

First introduced himself, then introduced the item.

TCP and UDP advantages and disadvantages, and under what circumstances to use?

How to determine the stability of the network?
mysql engine, injecting
TCP fourth wave, how to avoid entering timewait
TCP three-way handshake, why not twice?
http message composition (QAQ)
polymorphism of hiding and covering
inheritance and composition
in Linux under development experience

The client once sent two requests, how to distinguish which (taking into account the package is incomplete)?

Heap sort
IO multiplexing

 

 

 

User 7

Author: internship can not find food
link: https://www.nowcoder.com/discuss/223499?type=2&order=0&pos=11&page=1
Source: Cattle-off network

one side

1. Talk java container (HashMap blowing for a long time and ConcurrentHashMap).
2. Talk about jvm memory management mechanism (comparison with c and java spoke next, mainly explained in detail the process of creating the next object, said lower How to determine the object that was recovered (reachability analysis algorithm), garbage collection algorithm, Garbage collector).
3. Why use project redis to cache praise and dislikes? Data inconsistencies how to do? How to ensure persistent data?
4. python will it? c language would you? Front-end will it? ios will it? (know a little...)
5. To write a title bar, to a log file, which records a day visit ip, time, and so, I hope to obtain access per day. (I feel should be written shell, but I will not, said the interviewer can use java, but I forgot Java io of the api ...)
6. Testing understand it? Probably talk about, how to test a pen need to test?
7. Anything else you want to ask me?

Two faces

1. Will jvm is not it, talk about memory allocation. I blew a lot of objects created, the interviewer say you create an object only say, that other variables? Then probably write a program like this, there is what I ask of each variable?

public class A{
      int a;
      B b1 = new B();
      void fun(){
          int c;
          B b2;
    }
}

1. Talk about your project, right, painted about architecture. You use redis do caching, now suppose that you are a test, how many pit redis possible can you suggest? (Left unfamiliar redis tears)
2. Overloading and rewritten. Why should there be overloaded, and I can name a function name not do anything else? Talk about how you understand.
3. Algorithm problem: given an array to find the number that appear more than half the length of the array. (I have no brain directly with the hash table, the interviewer said, frowning optimizes No, I think for a long time thought out).
4. Let me write test cases to test algorithms questions and find out what program you write test cases based on written what bug. . (As leetcode I do, and not be judged on a variety).

User 8

Author: Jinpeng 201,903,071,839,583
link: https://www.nowcoder.com/discuss/222035?type=2&order=0&pos=14&page=1
Source: cattle off net

from nine to ten twenty surface
1. Computer network: url input Enter experienced what (originally thought that is very thin, the interviewer had a layer by layer directly say what each layer dry) , and later asked tcp, routers, switches, anyway, a set of computer network I get to rip off the force. 2. Data structures: I will not tell the truth map, say a quick row and merge (see I was too dishes may not ask) 3. (The interviewer may feel too much food I asked what I most familiar with) my uncle the advantages and disadvantages jvm, gc after a bit algorithms in terms of gc, and tags to organize for why the old era, what with the young for the young with the process of garbage collection, jvm tuning parameters. 4. Next earned ACID, transaction isolation level of a database, each detailed explanation. 5. Consistent hashing algorithm, let me talk about theory, under what scenario can talk directly to, Why! 6. ask me what I got, Java cas syn lock lock talked about the underlying implementation 7 What else do you want to ask me what the fundamental basis of feeling very important, especially important, write a project did not ask! ! Feeling cold ooo, ooo! I summarize the first side to commemorate the fall of trick! ! !