Tips:
Do not interview without experience, or the company you want to go to, must be fully prepared!
Baidu (123 pages)
A:
Talk about crawlers and optimizations in the project, and why jsoup was used instead of Python urllib
Tell us what you know about anti-crawler measures, and how to handle exceptions.
Do a website from what aspects to consider anti-crawler.
How to implement recharge in the project, locking mechanism and transaction annotations, how to ensure the consistency of the transaction.
Spring level to do transactions and database level to do the difference, their implementation.
Mysql’s default isolation level (repeatable read)
How to configure transaction propagation in Spring (XML vs. annotations, and use of Savepoint)
Algorithm: O(1) delete execution linked list nodes and do analysis (in fact, it is to point out the defects and hidden dangers of the direct copy value method in the finger offer)
Algorithm: the longest distance of a binary tree (recursive idea)
Friends in need can click:This! Point the, code word: J j.
Chat program
Talk about Spring’s IOC and AOP ideas
About AOP applications in Spring (such as transactions, notifications, aspectJ, slf4J principles, and log4j comparisons)
About JDK proxies and Cglib third-party proxies (tell the difference between interface proxies and subclass inheritance)
What database are you using
How large is the maximum amount of data, is it indexed and how is it used
Why indexes can’t be used casually, and when (when they don’t work, when they’re most efficient).
How to achieve the index overhead and performance balance, using a table to illustrate. (The method is to look at what queries are frequently used based on the situation, and then what query criteria are in order to ensure the most efficient index, but also to ensure that the index does not fail, avoid invalid overhead, and compare with the show profile and explain features.)
Does the database use a cache? Talk about redis (used as a cache, queue, and storage).
Is redis single-threaded or multi-threaded, for example?
What is included in CloumnFamily? How to split regions? How to use the fourth dimension version number (generally three versions by default)
Managers face
Integrated surface
Talk about family, hometown, work interests, hobbies, etc
Introduce the design of the project, including exception handling, database design, communication model design.
Tell me about your understanding of the JVM (highlights)
360
One side
Self introduction plus project
How is thread pooling optimized for crawler, data size
How to deal with network delay
How to choose the film of the same name, there is no better way.
The principle of anti-crawler, from low level to high level, how do you deal with it
Thread process distinction
Let’s talk about the difference in resources, sharing, not sharing
Which resources are shared
JVM memory model
Characteristics of stack area
Database left connection Right connection scenario
Give 200 arrays of 200 numbers and find the largest 200
Git rebase git rebase git merge
How to call a distributed database
Linux common commands to view memory and disk usage
360 2 face
Talk about the project, give some background. How
What are the most impressive modules and solutions? What about other projects? What I did with my teacher and what I didn’t write on my resume
The project experience is ok. What about the foundation? I think,
Let’s talk about the JVM you know, in the middle
The JVM details are
The memory model
The garbage collection
Generation and recycling algorithms
Which ones act as GC root
Characteristics of collector classification
Class loading mechanism and parental delegation model
Several loaders
How is tomcat class loading different? The loading order is not a parent model
What does concurrency pay attention to, the way threads synchronize, communication
Several synchronization differences
Pessimistic lock optimistic lock, how to achieve the bottom, the more detailed the better
Singleton pattern characteristics, several implementations, easily cause problems
How do I prevent memory leaks, and which ones are most likely to cause
How does JVM tuning check for memory leaks and optimize GC parameters
Write SQL query with date multiple test score table, each student’s highest score for each course, date to be accurate
Write using the having clause and subquery respectively
Write code to rotate the array to find a value
360 on three sides
Hr surface by
Talk about how to receive the project, how to communicate with Party A, the biggest problem encountered, how to overcome
How to coordinate your own project with your teacher’s project and schedule.
What hobby is there at ordinary times, how to arrange his time
Where do they shoot, what sports do they like, and when do they do them
Why our department? What do you think of other departments
We are doing mobile terminal background, like to play with mobile phones
How do you usually use the app? How often
Will you start a business in the future? Why
Future planning, career technology and life
Friends in need can click:This! Point the, code word: J j.
tencent
Tencent’s interview tests thinking ability very much, and there are often some unexpected questions, or intelligence questions. That’s interesting.
One side
Let’s draw the underlying structure of hashMap, hand-write code to make a URL parser, using the regular method and the data structure of hashMap.
Identify 2 to the n, write a function.
HTTP response header structure and parsing, using buffer (write a pseudo-code)
What is in the RESP header?
Find the 100 most frequent occurrences of massive data (when the memory is insufficient, you can first do hash fragmentation, and finally merge, each operation can use hashMap count, or you can do the hash function count)
Redis underlying implementation, zset data structure
JVM memory model, generation, cpu100%
Nio model
What does wakeup in selector mean
Select poll epoll
Arraylist.sort (see the idea of TimSort)
What do you think about Java and C
Second interview
Find a maximum of 1,000 numbers in 10 billion
What’s the disadvantage? It’s not evenly distributed.
Any other ideas (hash, count sort)
Then the partition idea based on partition (find the KTH starting partition, recurse on the right side on the left side, recurse on the left side, and finally determine the maximum k partition)
How can I quickly tell if I’m in the 10 billion numbers?
How much space can a process apply for?
How to ensure data security between processes? Thread?
Has there been any research done on safety?
Login authentication how to do, why to use MD5, is there any improvement (salt makes MD5 library difficult to solve), what way do you know wechat credit? What do you think we should do?
So in terms of communication security, how do you keep HTTP secure, idempotent, how do callbacks identify different requests for the same session, how do they differentiate between different sessions
TCP three-way handshake and Timewait explain how this works
Let’s talk about sliding Windows. What happens when they saturate
Is HTTP secure? HTTPS?
Get and POST requests
How to check network status (vmstat)
View UDP performance, how many UDP ports, when to use UDP?
Why not TCP?
Qq which use TCP which use UDP? For each case, why?
See Tencent or very love to ask network communication, big data processing.
Redis, MySQL, Liunx, Spring, Redis, BATJ, etc.
Friends in need can click:This! Point the, code word: J j.
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