java1

1. Self-introduction 
2. Tell me about one thing that impressed you the most and how to solve it. 
3. 4. How does the JAVA garbage collection mechanism work 
? How to realize AOP, there are several ways, talk about 
5. What is the difference between TCP/UDP, how to implement it, what is the difference, and where are they used 
? Map Tell me about your understanding of MAP, you have used several MAP sets, talk about them separately, and then talk about the performance of HsahMap, mainly about hash collision 
7. There are several ways to create threads, what is the difference between Thread and Runnable interface 
8. Briefly describe the ZTE Algorithm Competition you participated in 
9. Tell me about the chat tool you made. If you encounter a sudden freeze in the service, how to solve it 
10. Tell me about your understanding of the spring framework 
11. Mysql database, how to use the index. 
12. Do you know anything about distributed 
13. Do you know about data structures 
14. Why do you want to change careers to do software? 
15. String and StringBuffer 
16. Analysis of thread safety of HashMap and ConcurrentHashMap 
17．Heap sort, quick sort 
18. The four characteristics of the database, the isolation level of the database, 
19. What is the thread synchronization mechanism used for? Why did you choose this mechanism in the first place? 
20. Difference between mutex and condition variable? Are mutexes blocking? Why did you choose the blocking mechanism in the first place? 
twenty one. Message queue 
22．Knowledge of distributed systems