Ha, ha, ha! Did the Java programmer meet ali first and then meet the same interviewer?

preface

Before I start, let me laugh! What a fate, a group of friends to share his almost magical interview experience!

First, Qiu Zhao applied for the resume of Ele. me, but was rejected in the interview because it was too bad. Then he teased me about how difficult the interview of Ele. me was! Especially the project part, basic answer!

Then he mustered up his courage to go to Ali, but unexpectedly, he met the same interviewer. (I just want to ask: big guy job-hopping is also so fast?)

It is estimated that the parties are stupid!! But fortunately, the big guy interviews many people every day, should not recognize, otherwise how interview questions with how are almost? But whether we can pass this time depends on the follow-up notice!

Ok, here are the interview questions (because they are similar, they are put together)

One side

Java several basic data types
The number of bytes of each Java type
What is the upper limit of int, and what is the length of int on 32-bit and 64-bit operating systems
How are symbols represented in the operating system
Rewriting and overloading
Encapsulation, inheritance, polymorphism, and separate applications
What are the major parts of the design pattern, simple factory explanation + handwriting, problems existing in simple factory (reflection to solve)
What are the network layer protocols
The difference between multiprocess programming and multithreaded programming
How many parts of a process are there, the process heap and the process stack, and whether objects created by MALloc in C are on the heap or on the stack
What are HTTP requests? GET and POST are different
What is used in the request header indicates the size of the request body
Cluster index, why cluster index
Concurrency and parallelism
Java locks and principles
There were a lot of questions, I don’t remember…
With 100GB of data, suppose only 1G of memory, how to sort (without the idea of external row, if you design a new one)

Second interview

Introduction of a module in a previous project (database design, function implementation, etc.)
How to design the login permission table structure, how to define the permission data structure, how to store, how to control the front-end mapping, etc. (to cover every aspect of this module)
Cookie, Session, JWT, how to share the session globally
JWT authentication and authorization process, why to use private key, jwtToken why to include signature, how to define the public key
How to set up Ajax request headers
What are the HTTP request methods? GET and POST are different
Request to Tomcat process flow (network and Tomcat answers respectively)
TCP sliding window principle, why group forward, send and receive buffer queue optimization
How can I prevent SYN attacks
CRSF attack, how to resolve
MQ application scenarios, what problems can be solved, what components and patterns does RabbitMQ have
What about Redis distributed, Sentinel mode
Cache breakdown and cache avalanche
What design patterns and indexes were used in previous projects
Handwriting Factory model
Cluster index page split problem, is it necessary to use primary key index
Answer the page split question from the disk perspective
Rip code 1: merge sort
Hand rip code 2: Two-dimensional backpack problem

conclusion

After seeing the interview questions asked by the big guy, it was really not easy, and he could jump directly from Ele. me to Ali in such a short time, so he must be Daniel! Or Maybe Ari was fed up and hungry, and he just transferred over.

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