Preface
Qiu Zhao came, and facing the Ali that he was thinking of, even if Chun Zhao was severely beaten, he couldn't help but submit his resume again. In fact, the interview this time was even more dangerous, and I felt very stressful throughout the whole process, unlike when I was recruited in spring, I felt more comfortable.
Until the day before yesterday, I thought I was hanging up on the two sides, and wanted to confirm it. I didn’t expect it to be an unexpected gain. The two sides actually passed. I recently arranged the final and intersection, and I really burst into tears.
lz is also very good at himself, and the algorithm is really weak. It has always been his biggest pain point. Ugh. The first question of the written test was ac 0.6, and the test example was passed the next day, but I don’t know why the array was out of bounds when I ran the question, 0ac. Ugh. Fortunately, I finally got an offer!
The following is the text. The questions are in no order. They are all recalled.
In addition, I have prepared first-line interview materials and my original super-hardcore PDF technical documents for everyone, as well as many sets of interview questions I have carefully prepared for everyone. (Continuously updating), if you need it, just click here to download it directly ! Hope everyone can find the job they want!
Ali side:
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Trigger the new generation GC, if the total number of surviving objects is greater than the capacity of the survivor area, what to do
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If there are many tasks, the blocking queue of the thread pool will burst into which area of the memory
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Is the stack on the heap?
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What are the GC roots
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Can instance variables be GC root
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Know which GC algorithm, introduce
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Give a scenario, ask how to set JVM parameters
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I asked a lot of SQL tuning, whether various statements can hit the index, which ones can be hit, and how to optimize
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There are three fields ABC in a MySQL table. There are 1000 types of A, 1W types of B, and 10W types of C. How to set the combined index of ABC and how to use it
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The difference between Mybatis # and $
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Can the method in the Mybatis interface be different from the SQL name in the XML?
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How does Mybatis complete the mapping between SQL and methods in the interface (I answered how to configure it), do you know how it is implemented?
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Introduce Spring's IOC and AOP
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The server sends the IO stream to the client
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How much do you know about IO and NIO
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What are the threads of the state, how to switch
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The difference between Notify and notifyAll
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Introduce thread pools, where are the differences between different thread pools, and how do you usually use thread pools
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Data structure of MySQL index
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How much do you know about B+ trees
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Cookie and SessionId talk about
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How the lock is implemented
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Synchronized synchronized block and synchronized method, what are the locks respectively
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Singleton mode, the problems of hungry and lazy
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How does Volatile achieve visibility
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Introduce JMM
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Happen before you understand
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A happen before B, means A must be executed before B
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Among the hardest projects you have ever done, what is the hardest task and how to solve it
Ali two sides:
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What source code have you seen?
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What maps are available in Java, and how to implement them, specifically
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In addition to LinkedHashMap, you also know which ordered maps
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ConcurrentHashMap talk about
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Why is there a thread pool
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What are the types of thread pools? What's the difference? What are the parameters? What are the rejection strategies
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What kinds of blocking queues are there and what are the differences
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How to understand Java reflection
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How to understand Spring's IOC and AOP
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What resources will be loaded when the Spring project starts, and in what order
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What happens when the browser enters a URL? Let’s talk about the whole process
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Http talk about, what is the content of the request, what is the response
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Your written test score is so high, have you brushed a lot of questions? How to brush it?
Ali three sides:
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How much do you know about MySQL's high availability and high performance
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Taobao has 1000T of data and cannot be stored on a single machine. What should I do? Is there a way to access the server only once? How much do you know about consistent Hash
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What is the difference between MySQL and redis
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How to do MySQL data backup
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What is the underlying principle of Redis
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Why is Redis faster than MySQL
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Redis RDB may lose data, what to do
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Doesn't Redis AOF also write logs to disk? What is the difference between that and MySQL's IO? Why Redis is fast?
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How to do Redis master-slave replication
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How much do you know about distributed caching
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Do you know other NoSQL
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Talk about the advantages and disadvantages of Java and C
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Have you ever written the bottom layer in C
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A detailed talk about Java's G1 collector
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When will G1 stop the world
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Has the Linux operating system been used?
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How much do you know about distributed and middleware
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Describe your project in detail
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Do you think your current project can be expanded and optimized? Tell me about it
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What does the laboratory do? Why switch to the Internet? How many students from the laboratory switch to the Internet
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Have you posted a paper? Would the instructor be willing to intern?
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How much do you know about Ali's technology? How much do you know about the department?
Ali on all sides:
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Commonly used data structures for database indexes
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Have you seen the Juc source code? What is the realization principle of the lock?
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Can CAS talk in depth
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Talk about the builder mode
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Talk about the experience of the written test (the written test score is high)
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What books have you read
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Which book do you plan to read next
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Introduce the laboratory project
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What is the biggest challenge I have ever encountered, it can be said that the laboratory project, internship experience or own project
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How to solve this difficulty
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Is there any cooperation in the project?
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Current offer situation
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Self-evaluation
Ali's five faces (cross faces):
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Introduce the project, the source of the project, did you do it alone?
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How to do login verification
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Talk about ThreadLocal
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How does ThreadLocal avoid thread pollution (don't understand what it means)
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How to like it
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Redis persistence method
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MySQL storage engine difference
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Why is Myisam generally faster than InnoDB in read-only scenarios
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How to use Mybatis
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The difference between Mybatis # and $
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The difference between BeanFactory and ApplicationContext in Spring
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What are the scopes of beans in Spring and what are the differences
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Name a specific application scenario of prototype scope
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Which design patterns have been learned and which design patterns have been used
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A talk about the producer consumer model
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How to implement blocking queue
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Have you learned Linux (basically never)
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Under Linux, how to find all files in a directory and require the output order to be sorted according to the creation time of the files
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Give you a bunch of student information, including student ID and name, let you find the names of the top 10 students
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How to implement PriorityQueue
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How to find the root number 3 (I talked about the dichotomy, using the square of 2, 1.5, and 1.75 to compare with 3 in turn, narrow the interval until the accuracy requirement is reached)
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Your search method is too slow, can you optimize it (I ask: Do you want to ask about the knowledge of numerical analysis? The interviewer said: Yes, have you never studied numerical analysis?)
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Fibonacci sequence, find the value of the nth term (recursive and DP have been answered)
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If the length of the sequence is 100W, isn't your DP matrix very large? How to optimize? (Answer: Use two variables a, b to record the first two values, temp = a, a = b, b = a + temp, recursively)
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What is the shortest time interval between the hour, minute and second hands of a clock? (I have no idea at all, I only know that it will not work within an hour, because the speed of walking is different, and the fast and slow speeds in a circle cannot be hit)
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How do you usually study
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Which book I am reading recently, which book I plan to read next
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Pros and cons under self-evaluation
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How to prove your strong learning ability
to sum up
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Finally, what I want to say is that no matter what age you are now, what city you are located in, what background or education you have, the person you are compared to will always be yourself, so next year you will see if there is a gap with you this year. People who are salted fish can only use their best to jump. Wish, you will be better next year!
