Preface
This 211 master 211! There is never a right time, you will always feel that either is too young, or too old, or too busy, or for other reasons. If you are always troubled by not finding the perfect moment, then the perfect moment will never appear.
The purpose of writing
Because when I first learned java, I was often in the mud! I often think of relying on the online face to supplement myself. Now I am no longer the canned food who is often anxious and occasionally depressed, nor is it the shrimp who trembles and learns every experience and every skill. Everything is going to a good place. Hope this post can bring a ray of light to everyone who can't see the future, maybe everything is not so bad.
Autumn tricks
- Ali
- Byte sp
- Baidu ssp
- Meituan Cabbage
- Huawei 14
- Jingdong Cabbage
- Weibo sp
- A little bit of information ssp+
because I can’t remember many of them, I will pick out the important ones and write them down below.
In addition, I’m here to prepare interview materials from first-line manufacturers and my original super-hardcore PDF technical documents, as well as the ones I prepared carefully for you. Many sets of interview questions from major factories (constantly updated), friends in need, click here to remark csdn, and download by yourself ! Hope everyone can find the job they want!
Ali technical side
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Spring bean loading and instantiation process
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Have you seen the Spring AOP source code?
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java memory model
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If you are given a map with many objects in it, where is the map stored?
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GC algorithm?
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Talk about the CMS garbage collector
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Tell me about the challenges you feel in your project
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Talk about the gains of your project
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What database is used in your project
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What is the amount of data per day, your database
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What have you optimized
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How is the index created
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What if I have many fields that need to be indexed
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Mysql storage engine, which one are you using
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Talk about the underlying data structure of the Innodb database
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Features of B+ tree
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The difference between B+ tree and B tree?
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Talk about your commonly used APIs and packages
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A talk at the bottom of haspmap
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Is he thread safe
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So what is the corresponding thread-safe class in juc
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The underlying implementation of ConcurrentHashMap?
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Thread pool, which parameters, which types, and rejection strategies
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If the number of core threads is full and the blocking queue is full, then another task is to directly create non-core threads or enter the queue and then dequeue and create again
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Optimistic lock, pessimistic lock
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Is CAS implemented by hardware or software
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Is volatile a lock?
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In addition to wait and notifyall, is there any way to achieve similar functions
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Talk about a few apps that you usually like
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Taobao, how do you think he recommended
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What happened after the user placed the order
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What do you think is the difference between Taobao and Jingdong
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Netease Cloud Music, what do you think of his recommendation?
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If there are millions of music, I want to sort according to a certain column and only display the top 100, how to do it (TOP K)
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What do you want to ask
Ali two-sided technical
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Let’s talk about the project (30 minutes)
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You said you used UDP in your project, why don't you use TCP
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Then you elaborate on the difference between TCP and UDP
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What is the database used (MySQL)
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What is your data volume (several millions)
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What query optimization (index) did you do for these millions of items?
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How to build the index
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Why use time and id as index
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The isolation level of the database
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Do you know what is master-slave replication?
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Tell me about the rules for indexing
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JAVA class loading mechanism (load verification is ready to parse and initialize, and also talk about the parent delegation model)
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Talk about all the parameters of the thread pool
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The underlying implementation of ConcurrentHashMap
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Have you used RPC?
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What about the message queue?
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40 minutes
Ali three technical aspects
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Tell me about all the projects you have done and the books you read during the project
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Why do you use UDP instead of TCP? Let me talk about the difference in detail (again)
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How much data is in your database
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What have you optimized
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Why do you choose to delete data that is more than one week old
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If you keep this part of the data now, what would you do
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Save on another server, then the data will become larger and larger, and the final query will be very slow, how do you deal with it
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If you build an index on the history server, how and why
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Your rank in the class
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Have you participated in any competition
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What offer did your classmates get
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What do you think is their advantage over you
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Why don't you go for an internship
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What do you usually do in the laboratory
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What are the ways to communicate between threads (locking, memory barrier)
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The parameters of the thread pool are explained in detail (hat trick)
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NIO, tell me
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Why not use NIO for your project
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RPC, do you understand (don’t understand)
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I don’t understand, it’s okay, let me tell you about it (five minutes)
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Well, if you are now asked to design the rpc framework for remote calls, how do you design
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Write the pseudo code of the main functions of the client and server
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Have you participated in an interview with other companies
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Do you have an offer now
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One hour
to sum up
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