Java
1. Multiple threads simultaneously read and write, read threads zoomed far greater than the amount of the number of write threads, you think how to solve concurrency issues? Gash would you choose what kind of lock?
2. JAVA understanding of AQS whether it is dry place that is doing it?
3. In addition to the synchronized keyword outside, you are how to protect thread-safe?
4. What do I need to add the volatile keyword? It can ensure thread safe?
The thread pool thread if all busy, submit ⼀ a new task, students will be issued ⽣ what what? Queue column filled after all, still busy, and then submit what ⽣ will be issued even born?
6. Tomcat's own parameters you ⼀ generally how to adjust?
7. synchronized keyword is locked even what ⻄ East West? How in the bytecode is represented? Performance in-memory objects Why?
8. wait / notify / notifyAll ⽅ method requires not required to be included in the synchronized block? Why is that?
9. ExecutorService is how you usually use the Use? Each service is a put or a destination time which put a term? what is the benefit?
Spring
1. Have you ever used Use Spring's AOP? Is used to doing? Probably be how to use?
2. If a ⼀ interface has two different implementations, then how to achieve a specified Autowire?
3.Spring declarative transaction @Transaction notes generally written in what position? Throws an exception automatically rolls back it? There is no way to control not trigger a rollback?
4. If you want to create and implement their own logic later assembled in a Bean, you can achieve what way?
5.SpringBoot Why not put the container can run HTTP web service?
6.SpringBoot If you want to use custom configuration files rather than just application.properties, how should I get?
7.SpringMVC in RequestMapping can specify GET, POST method it? How to specify?
If the desired output SpringMVC Object (e.g.
8.XXResult or XXResponse) This package is JSON output, how they deal with?
9. How interception SpringMVC exceptions and then do custom processing, such as playing or log packaged as JSON
There is a 69 Spring Edition answer
MySQL
1. If you have a lot of data into MYSQL what way would you choose?
2. If the query is slow, what is the first way you can think of? The index is doing?
3. If you build a separate index, query time find out two, will use this separate index it?
4. If you build an index that contains multiple columns, query time only the first column, the index can not spend? Check it three?
5. Connect question, if the latter has a condition where i + 5 <100 uses the index to it?
6. how to see whether the use of an index?
7.like% aaa% will use the index it? Like aaa% do?
Drop, the difference between truncate, delete the?
8. Usually you is how to monitor database? SQL is how slow the investigation?
9. Do you support database emoji expression, if not, how to operate?
10. Is your single database table data volume is how much? How much time general began a sharp decline in query performance?
11 died query, the query process of trying to figure out what order execution? After you will usually find out why?
12. A separate read and write is how to do? You would think that the middleware how to operate? Such operations have anything to do with the transaction?
13. The sub-library sub-table have not done? The migration process line is kind of how? How to determine the data is correct?
JVM
1. Do you know what your line or what strategy to use GC? Is there any advantage for what scene?
2.JAVA class loader including several? Parent-child relationship between them is how? Parents delegate mechanisms mean? what is the benefit?
3. How to customize a class loader? Have you used or what class loader under what scenario you need a custom of it?
What parameters are set heap memory?
What data 4.Perm Space saved? Cause OutOfMemory it?
5. When do gc, what sequence of an object is moving in various Space memory is?
6. Have you ever encountered OutOfMemory problem? You are how to deal with this problem? What have you learned in the process there?
Perm Space there after 7.1.8 What has changed? MetaSpace default size is unlimited it? Will you to specify the size or in what way?
8.Jstack is doing? Jstat it? If the online program periodically Caton, you suspect may be the cause of gc, you will how to troubleshoot this problem? Thread log Usually you would see what part of it?
9.StackOverFlow anomalies have never met before? Generally you guess will be triggered under what circumstances? How to specify the stack size of a thread? How much do you usually write?
Linux command
1. Log particularly want to see only the last 100 lines of how Nongnong? If you want to have to look at continuous output log, what order?
2. If the log output side, while there is no want to see in real time how a keyword should get?
3.grep If you ignore how the case should get? Regular expression it?
4.vim down the line what is the key? 30 down the line it? What is the end of a line to jump to the file? Jump What came back? What searches are backward?
5. If there is a text file, press the space as a separator column, if you want to count the number of occurrences of each word in the third column should be how to get there?
6. If the number of occurrences of a row above sequence should be how to get? Want to order in the order of the numbers themselves rather than a string of how to get?
7.Linux environment variable is used as a separator of what? Command to set environment variables through what?
8. The right to set limits such as a file set 64 is what order? The 6 What does it mean?
If you want to see 9.Linux following a process of resource consumption is how to see? System load is probably referring to what does this mean? You online system load is generally much? If a 4-core machine, you think how much load is more normal? 1 click inside the top command what will happen?
10.top command inside, sometimes all processes CPU usage add up to more than 100% is how is it?
11. What view of system performance or for your command to find the problem? Which parameters do you usually see?
12. want to see an open process which the network connection is what order? Inside the state of connection you are more concerned about what kinds? - tricky question
have not done to optimize the system parameters of the Linux, probably optimize what?
13. The system parameters inside a man named backlog can be used to do?
14. The view network connections and found a lot TIMEWAIT may be the reason? What will be the impact on your application? In what ways would you choose to reduce these TIMEWAIT
15. Can tell us about the process of a TCP three-way handshake, and now if there is a network program, you send data to a third party library, this library you suspect data sent a problem, then how to verify? You usually how tcpdump analysis of the exported file?
16.KeepAlive is used to do? The advantage is what?
Redis - Development
1. Cache penetration can tell us about it? How do you think should solve this problem?
2. how do you trigger cache update? (Such as setting the timeout (passive mode), such as updating when the active update)? If this is how passive way to control multiple entry simultaneously triggered a cache update?
3. What do you do with Redis? Why not other KV storage cases such as Memcached, Cassandra, etc.?
4. What kind of Redis client? The reason Redis performance can probably say something?
5. Redis data structures which you are familiar? Zset is doing? What is the difference and set?
6.Redis of hash, storage and specific command to get the name?
7.LPOP and BLPOP difference?
8.Redis has some SCAN command contains the keyword is doing? SCAN amount of data returned is fixed it?
The 9.Redis Lua has not been used? What can be used to do? Why use something like this?
10.Redis the Pipeline is used to do -? Operation and maintenance
Redis persistence about ways what aof AOF and rdb difference is what advantages and disadvantages it???
Replication 11.Redis what the general process is the implementation process bgsave this command -?? Tricky question
12. If you have a lot of data to be stored KV Redis, but the lack of memory, the memory can be reduced by what means? Why can reduce memory?
13.Redis in List, HashTable have used the ZipList, Why did you choose it?
There is a 50 Redis version of the answer
Monitoring , stability
1. Business journal is by what means to collect?
2. How online machine monitoring? What is the use of open source products, or self-study products? It is the order of minutes or second-class?
3. If you were to think of ways to collect performance data for a JAVA back-end application, you'll care about what? You will choose what kind of tools, ideas to collect?
qi
4. Generally, when you call the third party will monitor the situation calls?
A problem inside
1.hashcode two equal classes must equal it? Equals what? Instead of it?
2. introduce a set of framework?
What is the difference 3.hashmap hastable underlying implementation? Hashtable and concurrenthashtable it?
What is the difference 4.hashmap and treemap? What low-level data structure?
The thread pool used it have what parameters? How to achieve the underlying?
6.sychnized What is the difference and Lock? Sychnize what happens is that the object lock? When is the global lock Why?
7.ThreadLocal is how what the underlying implementation? Write a chant example?
It works 8.volitile of?
9.cas know how to achieve it?
10. Please write a singleton with at least four written?
11. Please tell us about JVM memory model ?? what used to talk about all the garbage collector chant
12. Send online frequently full gc how to deal with? CPU usage is too high how to do?
13. How to locate the problem? How to solve the solution ideas and talk about treatment
14. bytecode knows? What are bytecodes? Integer x = 5, int y = 5, x = comparison step which have been y?
15. talk about class loading mechanism chant What are the class loader, the class loader which files are loaded?
16. handwriting about the class loader Demo
17. osgi know it? How did he achieve ???
18. Will the JVM to optimize what you have done? What methods to achieve what effect ???
19.classforName ( "java.lang.String") and String classgetClassLoader () LoadClass ( "java.lang.String") What is the difference ah?
20. The probe Tomcat operational mechanism that is the framework?
21. Analysis Tomcat threading model?
22.Tomcat understanding and tuning system parameters?
23.MySQL B + Tree underlying mechanisms?
24.SQL Detailed implementation plan?
25. Detailed index optimization?
26.SQL statements such as how to optimize?
27.spring what are the underlying mechanisms of how to achieve AOP ah ah IOC it ??
28.cgLib know? What is the difference between him and jdk dynamic proxy? A handwritten jdk dynamic proxy chant?
29. Use mysq1 index What are the principles?? What is the data structure of the index? What is the difference 3 + tree and B tree?
30.MySQL What storage engine ah? Are any difference? Learn more!
31. Design a high level of concurrent database system how to design a database lock ?? What type? How to achieve it?
32. The database transaction What?
33. How to design sub-library sub-table scheme can be dynamically expansion volume reduction of?
34. Which sub-library sub-table used middleware, so what advantages and disadvantages? Talk about your understanding of the underlying sub-library sub-table middleware implementation principle?
35. I did not have a sub-library sub-table system, minutes after the system needs to library sub-table, how to design, make sub-library sub-table is not dynamically switch the system to the system of sub-library sub-table? TCC? That if the network is The reason, the network even unreasonable how to do ah?
36. Distributed Transaction know? How do you solve?
37. Why did you library sub-table ah?
38.RPC communication theory, communication theory distributed
39. What are distributed addressing consistency hash algorithm know it? Handwriting java code that implements it ?? If you take userId touch slice, then I want to check how a continuous period of time the data do ???
40. How to solve the sub-library sub-table primary key implementation issues What ??
41.redis What is the difference and why the single-threaded memcheched redis higher than memched efficient multi-threaded ah?
42.redis what type of data which are used in the scene ah?
How do key redis main 43.reids from redis replication cluster model is how to realize is how to achieve that addressing ah?
44. How to use redis design distributed lock? Zk can use it? How to achieve ah which both higher efficiency ah ??
45. redis persistent know what the shortcomings are the advantages ah?? Specific underlying achieve it?
46.redis expiration policy LRU write about what are the java version of the code, right ??
47. talk about dubbo implementation process linked to the registry can continue to communicate it ??
48.dubbo which serialization protocol support? Hessian hessian talk about data structures PB PB know why efficiency is the highest ah ??
49. netty know it 'netty be doing it NIO, BIO, AIO is what ah What is the difference ah?
50.dubbo replication and high availability strategy balancing strategy what are ah dynamic proxy strategy?
51. Why the split system to split ah dubbo can not do 'dubbo and thrift What is the difference ah?
52. Why use Message Queue Message Queue ah What are the advantages and disadvantages ah?
53. How to ensure a highly available messaging queue ah how to ensure that messages are not repeated consumption ah
54.kafka, activemq, rabbitmq, rocketmq what are the advantages and disadvantages ah ???
55. If you had to write a message queue, how architected ah? Talk about your ideas
56. talk about TCP 'IP four?
57. The workflow ??? What are the differences http1.0 http1.1http2.0 specific ah?
58.TCP three-way handshake, four break workflow draw a flow chart Why not look at four or five times a second ah?
59. draw at https workflow? Specifically how ah? How to prevent capture ah ??
60. The source code used in classic design and common design patterns
61. How to choose the right system architecture log technology (log4j, log4j2, slf4j, jcl .......)
The relationship between the principle of 62.springAOP, springAOP and Aspectj of, springAOP source problem
Principle underlying communication framework 63.dubbo
64.RPC communication theory, communication theory distributed
65. How to use springCloud micro Services Architecture
66. The proper use of technology docker
The underlying principle 67.springMVC, from source to analyze how its principles
68.mybaits principle underlying implementation, how to analyze mybaits from source
Principle 69.mysql index, the index is how to achieve
70. The index of the underlying algorithms, how to properly use and optimize indexes
71.springboot how to quickly build systems
72.zk principle zk know what Paxos algorithm can know? Talk about the principle and implementation?
73. If you had to write a message queue, how architected ah? Talk about your ideas
74. Distributed Transaction know? How do you solve?
75. What would you have done JVM optimized? What methods to achieve what effect
This article is taken https://www.cnblogs.com/lwh-note/p/9495954.html