Ant Financial Service Side:

Afternoon hangzhou phone, ask if there is free, decisive free, although feel slightly nervous, a little meng.

Interview Topics:

1. The difference between HashMap and Hashtable
2. Implement a HashMap that guarantees the order of iterations
3. Let’s talk about sorting algorithms, stability, complexity
4. Say the GC
5. Guaranteed length of internship
6. Career planning

On the whole, there are many basic questions on one side, so the bloggers have basically answered them, and it is still useful to have prepared them. So it was good after one meeting, and then the next afternoon it was a second one.

[] (https://blog.csdn.net/m0_5918…Ant Financial’s second interview

2 face interview is my most worry, because the second interview is the key, is one of the biggest is in charge of the interview, so is critical, as a whole, the second the rhythm is very fast, and a completely different, the interviewer is very hope I simply say that finish the answer, so the surface is not very good, when finished thought GG again, but finally fortunately, interview questions as follows:

1. Introduce yourself.
2. How does the JVM load a class, and what methods are in the parent delegate model?
3. How is a HashMap implemented?
4. The difference between HashMap and Concurrent HashMap is that Concurrent HashMap is thread safe and how Concurrent HashMap guarantees thread safety.
5. HashMap differs from Hashtable, and is Hashtable thread-safe?
6. What are the ways of interprocess communication?
7. What regions is the JVM divided into, and what does each region do?
8. How does the JVM GC, Gen, Gen, Persistent, and what does it store?
9. Which of the reference accessibility analysis algorithms used by GC can be used as GC Roots objects?
10. Quick sort, process, complexity?
11. What is a binary balanced tree, how to insert a node, delete a node, say the key steps.
12. How does TCP guarantee reliable transmission? Three handshakes?
13. What is the difference between TCP and UDP?
14. Sliding window algorithm?
15. How does Linux process scheduling work?
16. What are the most common commands you use on Linux?
17. When does the operating system deadlock?
18. What are the common hash algorithms?
19. What is a consistent hash?
20. How do you understand distributed locking?
21. What are the paradigms in the database?
22. What is the structure of the index in the database? When is an index appropriate?
23. What are NIO, BIO, and AIO in Java?
24. What tools are used to debug the program? JConsole, have you used it?
25. Now a thread in the JVM is suspended. How to use the tool to find out the reason?
26. How is thread synchronization related to blocking? Is synchronization necessarily blocked? Is blocking always synchronized?
27. What’s the difference between synchronous and asynchronous?
28. Have you used thread pools?
29. How do I create a singleton pattern? Double checking, he says it’s not thread safe. How to efficiently create a thread-safe singleton?
30. What has been used under the concurrent package?
31. What are the commonly used databases? Has Redis ever used it?
32. Know about Hadoop? What are the components of Hadoop? HDFS, hive, hbase, zookeeper. Talk about the MapReduce programming model.
33. What open source protocols do you know about?
34. What open source software do you know?
35. What books have you been reading recently?
36. Do you have any questions to ask me?
37. What design patterns do you know? What design patterns have you used
38. How do you determine if a singly linked list has a ring?
39. How does the operating system schedule paging?
40. What is an anonymous inner class? How do I access variables defined outside of them?

In the second interview, the interviewer asked urgently and I answered quickly, so I did not answer the two questions well. However, the interviewer made me feel a sense of respect, because he spoke quickly, but he could get to the point, and the most important words were very acceptable.

After the second interview, I got three phone calls that evening (I was really amazed at Ali’s efficiency)

Ant Financial has three sides

The three interviews are mainly about my project. After the previous interviews, I have gained a high interview experience at this time, so I don’t panic at all and answer the questions calmly. The three questions are as follows:

1. Introduce yourself and what projects you have done.
2. JAVA virtual machine area how divided, each area kinetic energy, this piece of free play.
3. Which class loaders are loaded from top to bottom in the parent delegate model, and which classes are loaded?
4. Is it possible for a parent class loader and a child class loader to load the same class? If the same class is loaded, which class should be used?
5. How are the structures of HashMap, get(), put(), implemented? What are the problems with HashMap?
6. ConcurrentHashMap get(), put(), and so on. What are the problems with ConcurrentHashMap? Is ConcurrentHashMap a read lock or a write lock?
7. Differences between HashMap and Hashtable
8. What is the difference between a sleep() and a wait() method? How is synchronized implemented under the hood? What’s the difference between a block of code and a method?
9. What is a thread pool? If you were to design a dynamically sized thread pool, how would you design it? What are the methods?
10. What is a deadlock? JVM thread deadlock, how can you tell what is the cause? If I use VisualVM and dump the thread information, what information will it have? That’s a lot of questions… I’m confused because I haven’t actually done the = =
11. What commands have you used to view heap and thread information in the JVM virtual machine? I’ve only ever used VisualVM…
12. What are the garbage collection algorithms? Does CMS know? How does it work?
13. What is a transaction in a database? The isolation level of the transaction? What are the four characteristics of transactions? What are dirty reading, phantom reading, and unrepeatable reading?
14. What is the structure of a database index? I say B tree and B plus tree, and he says those are the only two. I said full-text inverted index again. Then we introduce the structure of the B+ tree.
15. How to write a paging query statement in a database?
16. What is a consistent hash? To solve what problem?
17. How does Redis’s storage structure, or how it works, differ from MySQL? What are the data types?
18. Redis is used in the project, why Redis, know about other NoSQL databases? How do you use Redis in your projects? What is key? What is value?
19. Merge sort? Time complexity? Spatial complexity?
20. What sort do you usually use? Quick sort. Talk about what situations it works in and what situations it doesn’t work in.
21. What do you do on a project? Because I used Solr, he asked me how does Solr work?

The last

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