The interview process with lots of spelling is a little cumbersome , But frankly pdd This year has given me a very good social recruitment experience . In terms of the content of written test questions and anti cheating preciseness, it is ahead of other companies , In the interview notice email, we also attached a picture of the hotel .

Pinduoduo Java one side

HashMap and HashTable as well as CocurrentHashMap detailed description

* network IO Model ? What is multiplexing IO?select and epoll The difference between ?
* TCP The process of three handshakes , What's wrong with a third handshake ?
* What are the common thread pools ? Their application scenarios ?
* Java Class loading mechanism ? Benefits of the parental delegation model ?
* JAVA How much do you know about outsourcing components ?
* When will multi thread deadlock occur ? How to prevent it
* The switching conditions of user mode and core state of operating system and why to switch
* Characteristics of database transaction ? Transaction isolation level ? Transaction implementation in project ? Dirty reading , Non repeatable , Let's take an example of fantasy reading ?
Pinduoduo Java Dihedral

* Database index ?B+ tree ? Why index ? What kind of fields need to be indexed , What do you usually consider when building an index ? Does the index cause insertion , The efficiency of deletion becomes low , How to solve it ( Sub table )?
* Design patterns , Singleton mode , How to ensure thread safety ? Lock efficiency is too low , How to improve efficiency ?
* CAS?CAS What is the essence ? What is atomicity ?Compare and Swap Two steps *** do , Why is atomicity guaranteed ( Involving CPU instructions )?
* What do distributed lock implementations know ? Which lock do you prefer ?
* Redis What are the persistence operations for ?
* How to use it redis Processing hot data
Pinduoduo Java Three sides

* What Message Queuing Middleware have you contacted ? How to select the type ?
* Talk about you SOA And the understanding of microservices ?
* Talk about it in detail Spring Cloud Services and registration ?
* Distributed cap Do you understand , What do they mean ?
* Network programming nio and netty relevant ,netty Thread model of , Zero copy implementation ?
Pinduoduo Java Four sides

* Redis Single thread or multi thread ?Redis How to do distributed cluster ?
* Do you know about cluster avalanches ?
* Peak clipping in high concurrency scenarios , Realization of current limiting ?
* The project you worked on was the most satisfactory , Talk about your architecture design ideas ?
* future 2 What is the plan for the year ?
How much to spell Java Five sides (HR)

* ​ Why leave from the last company ?
* Why choose here ?
* How to treat overtime ?
* How do you usually learn technology , except Java relevant , What other technologies will you learn about ?
* What is the expected salary ?
Share some interview specific exercises PDF file , Friends in need can click three times after “ Add me VX Assistant ” You can get it for free !


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