2020 is the most difficult season for recruitment interviews. Many big companies, such as Tencent and Byte, have significantly reduced their recruitment quotas, but have repeatedly raised the threshold for interviews. If they do not prepare carefully, they may be dumbfounded by the interviewer. Today, let’s talk about the things I interviewed as an interviewer.
Counting from the person in charge of an e-commerce project to the later chief architect, I interviewed at least 300 job applicants. I dare not say that every colleague who has successfully joined the company has developed particularly well, but most of them are still very good.
A strong technical foundation is the most basic assessment requirement. Many friends who come to apply for the job still have the foundation, but their knowledge is too narrow. So what are the key assessments for Internet companies, especially the e-commerce industry? Recently, I have sorted out the assessment knowledge that I have frequently asked in these years. There are no less than 100, including many mandatory test sites, high-frequency points, and salary increase points for large companies. These are also often encountered in daily projects as a developer. Of trampling.
For your convenience, I have made a classification of these points, which are divided into 5 categories, namely: JVM, mysql, Redis, MongoDB, Dubbo . I have disassembled and thought about these issues and sorted them into a pdf. Due to space limitations, I will not list them all here. Students who need it can get it at the end of the article, hoping to inspire and gain from it.
Here are the real interview questions to share directly with you, specifically:
JVM
- Will there be a memory leak in java? Please describe briefly.
- In 64-bit JVM, the length of int is the majority?
- What is the difference between Serial and Parallel GC?
- For 32-bit and 64-bit JVMs, the length of int type variables is the majority?
- What is the difference between WeakReference and SoftReference in Java?
- What does the JVM option -XX:+UseCompressedOops do? Why use
- How to judge whether the JVM is 32-bit or 64-bit through a Java program?
- What is the maximum heap memory of 32-bit JVM and 64-bit JVM?
- What is the difference between JRE, JDK, JVM and JIT?
- Explain Java heap space and GC?
- JVM memory area
- Program counter (thread private)
- Virtual machine stack (thread private)
- Local method area (thread private)
- Can you guarantee GC execution?
- How to get the memory used by the Java program? What percentage of the heap is used?
- What is the difference between heap and stack in Java?
- Describe the principle and mechanism of JVM loading class files
mysql
- Database storage engine
- InnoDB (B+ tree)
- TokuDB (Fractal Tree-node with data)
- MyIASM
- Memory
- What are the database engines
- The difference between InnoDB and MyISAM
- index
- Common indexing principles are
- What are the three paradigms of the database
- First Normal Form (1st NF-the columns are not subdivided)
- Second Normal Form (2nd NF-each table only describes one thing)
- The third normal form (3rd NF-there is no transitive dependency on non-primary key columns)
- Database is transaction
- SQL optimization
- Simply talk about the difference between drop, delete and truncate
- What is a view
- What is inner join, left outer join, right outer join?
- What are the problems caused by concurrent transactions?
Redis
- What is Redis?
- How is Redis different from other key-value stores?
- Redis data type?
- What are the benefits of using Redis?
- What are the advantages of Redis over Memcached?
- What are the differences between Memcache and Redis?
- Is Redis single-process single-threaded?
- What is the maximum storage capacity for a string value ?
- Redis persistence mechanism
- Cache avalanche, cache penetration, cache warm-up, cache update, cache degradation, etc.
- What are hot data and cold data
- Why is single-threaded redis so fast
- Redis data types and usage scenarios of each data type
- Redis's expiration strategy and memory elimination mechanism
- Common Redis performance problems and solutions?
- Why is Redis's operation atomic and how to ensure atomicity?
- Redis transaction
- What is the persistence mechanism of Redis? Their advantages and disadvantages?
MongoDB
- What is mongodb?
- What are the characteristics of mongodb?
- What do you mean by NoSQL database? What is the direct difference between NoSQL and RDBMS? Why use and not use NoSQL database? Talk about the advantages of NoSQL database?
- What types of NoSQL databases are there?
- What is the most basic difference between MySQL and MongoDB?
- How do you compare MongoDB, CouchDB and CouchBase?
- What makes MongoDB the best NoSQL database?
- Will journal playback encounter problems when the entry is incomplete (for example, there happens to be a midway failure)?
- What is the role of the analyzer in MongoDB?
- What is a namespace?
- If the user removes the attribute of the object, is the attribute deleted from the storage layer?
- Can the log feature be used for safe backup?
- Are null values allowed?
- Update operation fsync to disk immediately?
- How to perform transaction/locking?
- Why is my data file so large?
- How long does it take to enable backup failure recovery?
- What is master or primary?
Dubbo
- Why use Dubbo?
- What are the layers of Dubbo's overall architecture design?
- What communication framework is used by default, are there other options?
- Is the service call blocking?
- What registry is generally used? Are there other options?
- What serialization framework is used by default, and what else do you know?
- What is the principle that the service provider can achieve the failure kick-out ?
- Why does the service launch not affect the old version?
- How to solve the problem of too long service call chain?
- What are the core configurations?
- What protocol does Dubbo recommend?
- Can a service be directly connected to the same service when there are multiple registrations?
- Draw a flowchart of service registration and discovery?
- How many solutions does Dubbo cluster fault tolerance have?
- Dubbo service is downgraded, what should I do if I fail to retry?
- What problems did you encounter during the use of Dubbo?
- How does Dubbo Monitor work?
- What design patterns does Dubbo use?
to sum up:
The document includes the technical points of spring family bucket, mybatis, MySQL, jvm, etc., hoping to help you sprint to the golden nine silver ten.