Foreword:
Excited heart, trembling hands, just want to walk to Dachang. This is my long-cherished wish, and the Emperor has lived up to it. At the end of last month, I was still immersed in crud every day. Suddenly I received an interview invitation from the back-end of Douyin. The resume was delivered in October. It was like a stone thrown into the ocean for so long, without splashing the slightest wave. Even I have forgotten that I still submitted a resume. I participated in this interview with full confidence. I felt confident that I would be able to win the offer. I did not expect to be brutally abused by the interviewer and told me that I must be next time!
one side
- CtrlC can terminate the program, can we do some other operations when the program terminates?
- tcp wave four times
- The difference between process and thread
- What are the methods of inter-process communication
- The bandwidth of 100Mbps is used by three people, and each person is 50Mbps. How does tcp guarantee the speed?
- How to deal with 1000qps stand-alone?
- Algorithm question: a super long number (there are dozens of digits), allowing any two-digit exchanges any number of times, what is the smallest number larger than it is obtained
- Briefly describe the similarities and differences between synchronized and java.util.concurrent.locks.Lock?
- A general explanation of the several available states of threads
- What is ThreadLocal?
- The difference between run() and start().
- Please tell me the thread synchronization method you know.
- Thread scheduling and thread control.
- What is a thread starving to death, and what is a livelock?
- What is the busy loop in multithreading?
- What is a volatile variable? What is the difference between volatile variables and atomic variables?
Two sides
- Why do you want to come to Douyin
- Briefly describe the paging and segmentation mechanism
- What does http's 501, 502, 503, 504 mean
- What is the operating system process status
- What is the location of nginx
- The difference between http and https, why can't it be upgraded from http to https
- What is pyc and when is it generated
- Algorithm question: To implement an LFU*** requires the implementation of set and get methods, and the complexity is O(1).
- (The LFU*** of this question is a storage space with capacity, which is an integer n. It stores key-value pairs. The frequency of each access to this kv pair is increased by one. If the new set kv pair has reached the upper limit of capacity , Delete the kv pair with the lowest frequency)
- What is GC? Why is there a GC?
- Briefly describe the Java garbage collection mechanism.
- How to judge whether an object is alive? (Or how to determine the GC object)
- The advantages and principles of garbage collection. And consider two recycling mechanisms.
- What is the basic principle of the garbage collector? Can the garbage collector reclaim memory immediately? Is there any way to proactively notify the virtual machine for garbage collection?
to sum up:
Through this interview, I also know my shortcomings and areas for improvement. Although my long-cherished wish to enter a large factory has not been realized, I still want to thank the interview experience! In addition, I think this time The most important question in the interview is that I didn’t review the past and learn the new. I didn’t go. I didn’t even read more interview questions. I also took advantage of this time to collect high-frequency interviews from major companies this year. Question, I will share it with you now. I hope you don’t run into a headless fly like me. If you ask something, you will kneel during the interview! As for me, I also have to regain my confidence, regroup, gnaw more interview questions, and fight the big factory again! I wish you a lot of offers!
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