2023 spring recruitment is coming, many students will ask is it necessary to memorize stereotyped essays for Java interviews?
My answer is: very necessary . You can hate this model, but you must memorize it, because if you don't memorize it, you won't be able to enter a big factory.
The Internet interview in China is probably the existing system that is closest to the imperial examination system.
Moreover, my country's stereotyped essay is indeed unique. Taking the United States as an example, North American engineer interviews pay more attention to algorithms (Coding). In recent years, Design rounds (system design and object-oriented design OOD) and BQ rounds (Behavioral question, behavioral interview questions) will also be added.
So why doesn't the domestic interview adopt such an inspection method? To put it simply, there are too many job seekers in the Internet IT industry. If you are looking at clear algorithm questions and design questions, then the interviewer will be required to have a very high technical level, and it will take a lot of time and energy.
Perhaps the current stereotyped essay interview is not the best solution, but it is indeed the most in line with the current domestic IT environment.
Therefore, after I interviewed more than 20 senior interviewers from big factories, I have been trying to refine and accurately organize a set of practical stereotyped essays. Now 329 fans have entered their ideal positions through this set of questions, so I share them Let everyone see, if there are any deficiencies, please comment and add.
1. Java basics 44 courses
1. Explain what is object-oriented? What is the difference between object-oriented and process-oriented?
2. What are the three major characteristics of object-oriented? Explain separately?
3. What is the relationship between JDK, JRE, and JVM?
4. What is the difference between overloading and rewriting?
5. Can a private or static method be overridden in Java?
6. What are the characteristics of the construction method?
7. What is the effect of defining a constructor that does nothing and takes no parameters in Java?
8. How many ways to create objects in Java?
9. What is the difference between an abstract class and an interface?
10. What is the difference between static variables and instance variables?
11. 12. short s1 = 1; s1 = s1 + 1; what's wrong? What about short s1 = 1; s1 += 1;? Is there any mistake?
12. What is the difference between Integer and int?
13. The difference between boxing and unboxing
14. Can the switch statement act on byte, long, or String?
15. The difference between 16, final, finally, and finalize
16. What is the difference between == and equals?
17. If the hashCode() of two objects is the same, must equals() be true?
18. Why do you have to rewrite the hashCode() method when rewriting equals()?
19. What is the difference between & and &&?
20. What about passing values when passing parameters in Java? Or pass by reference?
21. What is Math.round(-1.5) equal to in Java?
22. How to implement object cloning?
23. What is the difference between deep cloning and shallow cloning?
24. What is Java serialization and how to implement Java serialization?
25. When is serialization required?
26. How does generics work in Java? What is type erasure?
27. What are qualified wildcards and unqualified wildcards in generics?
28. What is the difference between List and List?
29. What is the meaning of reflection in Java? What are the application scenarios?
30. What are the advantages and disadvantages of reflection?
31. What is a dynamic proxy in Java? What are the applications?
32. How to implement dynamic proxy?
33. What does the static keyword do?
34. What does the super keyword do?
35. What is the difference between bytes and characters?
36. Why is String designed as an immutable class?
37. What is the difference between String, StringBuilder, and StringBuffer?
38. What is the principle of String string modification?
39. Is String str = "i" the same as String str = new String("i")?
40. What are the commonly used methods of the String class?
41. After modifying StringBuffer with final, can it append?
42. Classification of IO streams in Java? Name a few implementation classes you are familiar with?
43. What is the difference between byte stream and character stream?
44. What is the difference between BIO, NIO, and AIO?
2. 9 Java exceptions
1. When is the code in the finally block executed?
2. Will finally be executed?
3. In try-catch-finally, if there is a return in the catch, will finally still be executed?
4. Which part of try-catch-finally can be omitted?
5. What is the difference between Error and Exception?
6. How are runtime exceptions different from checked exceptions?
7. What is the difference between throw and throws?
8. What are the common exception classes?
9. Can the main thread catch the exception of the child thread?
3. Java Collection 24
1. What are the commonly used containers in Java?
2. What is the difference between ArrayList and LinkedList?
3. What is the function of ArrayList implementing RandomAccess interface? Why doesn't LinkedList implement this interface?
4. The expansion mechanism of ArrayList?
5. What is the difference between Array and ArrayList? When is it more appropriate to use Array?
6. What is the implementation principle/underlying data structure of HashMap? JDK1.7 and JDK1.8
7. What is the execution process of the put method of HashMap?
8. What is the execution process of the get method of HashMap?
9. What is the execution process of the resize method of HashMap?
10. Why must the size of HashMap be an integer power of 2?
11. HashMap multi-threaded infinite loop problem?
12. Can the get method of HashMap determine whether an element is in the map?
13. What is the difference between HashMap and HashTable?
14. What is the difference between HashMap and ConcurrentHashMap?
15. What is the difference between HashTable and ConcurrentHashMap?
16. What is the implementation principle of ConcurrentHashMap?
17. What is the implementation principle of HashSet?
18. How does HashSet ensure that elements are not repeated?
19. What is the implementation principle of LinkedHashMap?
20. How to use Iterator? What are the characteristics?
21. What is the difference between Iterator and ListIterator?
22. What is the difference between Iterator and Enumeration interfaces?
23. What is the difference between fail-fast and fail-safe?
24. What is the difference between Collection and Collections?
4. Java Concurrency 42 Ways
1. What is the difference between parallelism and concurrency?
2. What is the difference between a thread and a process?
3. What is a daemon thread?
4. How many ways to create threads?
5. What is the difference between Runnable and Callable?
6. Thread state and transition?
7. What is the difference between sleep() and wait()?
8. What is the difference between run() and start() of a thread?
9. How to ensure the safety of multi-threaded operation in Java programs?
10. How many methods of Java thread synchronization?
11. How does the Thread.interrupt() method work?
12. Talk about your understanding of ThreadLocal?
13. In which scenarios will ThreadLocal be used?
14. Tell me about your understanding of the synchronized keyword?
15. How to use synchronized in the project?
16. Tell me about the bottom-level optimizations of the synchronized keyword after JDK1.6. Can you introduce these optimizations in detail?
17. Talk about the difference between synchronized and ReenTrantLock?
18. What is the difference between synchronized and volatile?
19. Tell me about your understanding of the volatile keyword?
20. Tell me about your understanding of ReentrantReadWriteLock?
21. Tell me about your understanding of pessimistic locks and optimistic locks?
22. What are the two common implementations of optimistic locking?
23. What are the disadvantages of optimistic locking?
24. What are the usage scenarios of CAS and synchronized?
25. Briefly talk about the understanding of atomic classes in Java?
26. What is the principle of atomic?
27. Tell me about your understanding of the synchronizer AQS?
28. What is the principle of AQS?
29. What are the resource sharing modes of AQS?
30. The bottom layer of AQS uses the template method pattern. Can you name a few methods that need to be rewritten?
31. Tell me about your understanding of semaphore Semaphore?
32. What is the difference between CountDownLatch and CyclicBarrier?
33. Tell me about your understanding of the thread pool? Why use a thread pool?
34. What are the parameters for creating a thread pool?
35. How to create a thread pool?
36. How to set the number of threads in the thread pool? What issues need to be considered?
37. What is the difference between execute() method and submit() method?
38. Tell me about your understanding of Fork and Join parallel computing framework?
39. What concurrent containers are provided in JDK?
40. Talk about the understanding of CopyOnWriteArrayList?
41. Talk about the understanding of BlockingQueue? What implementation classes are there?
42. Talk about the understanding of ConcurrentSkipListMap?
Five, Java JVM 42 ways
1. Tell me about the main components of Jvm? and its role?
2. Talk about the understanding of the runtime data area?
3. What is the difference between heap and stack?
4. What is stored in the heap? What is stored in the stack?
5. Why should the heap and the stack be distinguished? Isn't it possible to store data in the stack?
6. What about passing values when passing parameters in Java? Or pass by reference?
7. How is the size of a Java object calculated?
8. What are the two ways of accessing and locating objects?
9. What are the methods for judging that garbage can be recycled?
10. Where does garbage collection start?
11. Will objects marked as garbage be recycled?
12. Tell me about your understanding of references in Java?
13. Talk about the understanding of memory leaks?
14. What is the root cause of memory leaks?
15. What are some possible memory leaks?
16. How to avoid memory leaks?
17. What are the commonly used garbage collection algorithms?
18. Why use the generational collection algorithm?
19. What kind of garbage collection algorithm should be used for the young generation and the old generation under generational collection?
20. What is floating litter?
21. What is memory fragmentation? How to solve?
22. What are the commonly used garbage collectors?
23. Tell me about your understanding of the CMS garbage collector?
24. Tell me about your understanding of the G1 collector?
25. Tell me about your understanding of garbage collection strategy/timing of garbage collection?
26. Tell me about your understanding of memory allocation? How are large objects allocated? Space Allocation Guarantee?
27. Tell me about the JVM monitoring tools you have used?
28. How to use monitoring tools to tune?
29. Some parameters of JVM?
30. Tell me about your understanding of the class file structure? What are the components?
31. Tell me about your understanding of the class loading mechanism?
32. What are the functions of each stage of class loading?
33. What class loaders are there? What is the role of each?
34. What is the relationship between class and class loader?
35. Tell me about your understanding of the parental delegation model? work process? why use
36. How to implement a custom class loader? What should I pay attention to?
37. How to break the parent delegation model?
38. What practical scenarios need to break the parental delegation model?
39. Tell me about your understanding of compile-time optimization and runtime optimization?
40. Why does the HotSpot virtual machine use an architecture where an interpreter and a compiler coexist?
41. Tell me about your understanding of the Java memory model?
42. What are the interactive operations between memories? What rules need to be met?
6. SSM framework 37 channels
1. What are the benefits of using the Spring framework?
2. Explain what is AOP?
3. What are the methods of AOP proxy?
4. How to implement JDK dynamic proxy?
5. The basic concepts of AOP: aspect, connection point, entry point, etc.?
6. What are the types of Advice?
7. Tell me about your understanding of IOC?
8. Bean life cycle?
9. What is the scope of a bean?
10. Do you understand the thread safety issues of singleton beans in Spring?
11. Tell me about your understanding of things in Spring?
12. Transaction isolation level in Spring?
13. Thing propagation behavior in Spring?
14. What are the commonly used injection methods in Spring?
15. What design patterns are used in the Spring framework?
16. What are the common implementations of ApplicationContext?
17. Tell me about your understanding of the MVC pattern?
18. How does SpringMVC work/execute?
19. What are the core components of SpringMVC?
20. What are the commonly used annotations in SpringMVC?
21. What is the role of @RequestMapping?
22. How to solve the problem of Chinese garbled characters in POST requests, and how to deal with GET requests?
23. Is the controller of SpringMVC a singleton mode? If so, what problems will arise and how to solve them?
24. How does SpringMVC set redirection and forwarding?
25. How is the interceptor written in SpringMVC?
26. What are the differences between SpringMVC and Struts2?
27. Tell me about your understanding of MyBatis?
28. What are the pros and cons of MyBaits?
29. What is the difference between MyBatis and Hibernate?
30. What is the difference between #{} and ${} in MyBatis?
31. How does MyBatis perform pagination? What is the principle of the pagination plugin?
32. How many pagination methods does MyBatis have?
33. What is the difference between MyBatis logical paging and physical paging?
34. Does MyBatis support lazy loading? If supported, how is it implemented?
35. Tell me about the first-level cache and second-level cache of MyBatis?
36. What Executors does Mybatis have?
37. What does MyBatis dynamic SQL do? What kind of dynamic SQL? Can you briefly describe the execution principle of dynamic SQL?
7. MySQL 31 channels
1. Please tell me about your understanding of the MySQL architecture?
2. What is the execution flow of a SQL statement in the database framework?
3. What are the three normal forms of the database?
4. What is the difference between char and varchar?
5. What is the difference between varchar(10) and varchar(20)?
6. Tell me about your understanding of indexing?
7. What data structure is used at the bottom of the index?
8. Tell me about your understanding of B+ tree?
9. Why does the InnoDB storage engine choose B+ tree instead of B tree?
10. Tell me about your understanding of clustered indexes?
11. Tell me about your understanding of hash indexes?
12. Tell me about your understanding of covering indexes?
13. What is the classification of the index?
14. Tell me about your understanding of the leftmost prefix principle?
15. How do I know whether the created index has been used? Or how can I know why this statement runs so slowly?
16. Under what circumstances will the index become invalid? That is, the query does not use the index?
17. How to optimize query performance?
18. Comparison between InnoDB and MyISAM?
19. Tell me about your understanding of horizontal and vertical segmentation?
20. Which three threads are involved in master-slave replication?
21. What are the reasons and solutions for the delay of master-slave synchronization?
22. Tell me about your understanding of database read-write separation?
23. Could you please describe the characteristics of the transaction?
24. Tell me about your understanding of the transaction isolation level?
25. Explain what dirty reading, non-repeatable reading and phantom reading are?
26. What is the default isolation level of MySQL?
27. Tell me about your understanding of MVCC?
28. Tell me about row locks and table locks in MySQL?
29. What are the lock algorithms of the InnoDB storage engine?
30. What are the methods for troubleshooting MySQL problems?
31. What should he do if the CPU of the MySQL database soars to 500%?
8. Redis 12 channels
1. Tell me about your understanding of Redis?
2. What are the general usage scenarios of Redis?
3. What are the common functions of Redis?
4. What data types does Redis support?
5. Why is Redis so fast?
6. What is cache penetration? How to deal with it?
7. What is cache avalanche? How to solve it?
8. How to ensure the consistency of cache and database data?
9. How many ways are there for Redis persistence?
10. How does Redis implement distributed locks?
11. What are the Redis elimination strategies?
12. Redis common performance problems and solutions?
9. Computer network 45 courses
1. Why is there a three-way handshake? Not twice?
2. Why do we need to wave four times? Not three times?
3. What is the difference between TCP and UDP? respective application scenarios?
4. Version differences between HTTP1.0, 1.1, and 2.0
5. What is the difference between POST and GET? respective application scenarios?
6. What are the common status codes and usage scenarios of HTTP?
7. What is the difference between HTTP status codes 301 and 302, and what are their uses?
8. If the data transmission is over during the interaction process, what should I do if I don’t want to disconnect the connection? How to maintain it?
9. How does HTTP implement long connections? When will it time out?
10. How does TCP ensure effective transmission and congestion control principles
11. What are the classifications of IP addresses?
12. Significance of URL encoding in GET requests
13. What is SQL injection? for example?
14. Talk about XSS attack, give an example?
15. Tell me about the five-layer model of the network. What is the responsibility of each layer?
16. Briefly explain the difference between HTTPS and HTTP
17. The difference between symmetric encryption and asymmetric encryption
18. Briefly, what are the network protocols corresponding to each layer?
19. How does the ARP protocol work?
20. What are the main characteristics of TCP?
21. What are the main characteristics of UDP?
22. What are the common application layer protocols corresponding to TCP and UDP?
23. Why does the TIME-WAIT state have to wait for 2MSL?
24. What is the function of the keep-alive timer?
25. How does the TCP protocol ensure reliable transmission?
26. Tell us about your understanding of the stop-and-wait protocol?
27. Tell me about your understanding of the ARQ protocol?
28. Tell me about your understanding of sliding windows?
29. Tell me about your understanding of flow control?
30. Tell me about your understanding of TCP congestion control? What algorithms are used?
31. What is sticky package?
32. How are TCP sticky packets generated?
33. How to solve unpacking and sticking?
34. What is the difference between forward and redirect?
35. What are the HTTP methods?
36. What is the process from entering a URL address in the browser to displaying the homepage?
37. DNS resolution process?
38. Tell me about your understanding of domain name caching?
39. Talk about your understanding of HTTP long connection and short connection? Which scenarios are they applied to?
40. How does HTTPS work?
41. What is the difference between HTTP and HTTPS?
42. What are the pros and cons of HTTPS?
43. What is a digital signature?
44. What is a digital certificate?
45. What is the difference between Cookie and Session?
10. Operating system 32 channels
1. Briefly talk about your understanding of concurrency and parallelism?
2. The concepts of synchronous, asynchronous, blocking, and non-blocking
3. Basic concepts of processes and threads
4. What is the difference between a process and a thread?
5. Why do we need threads when we have processes?
6. Process state transition
7. What are the communication methods between processes?
8. What are the scheduling algorithms for processes?
9. What is deadlock?
10. What is the cause of deadlock?
11. What are the necessary conditions for deadlock to occur?
12. What is the basic method to solve deadlock?
13. How to prevent deadlock?
14. How to avoid deadlock?
15. How to remove deadlock?
16. What is buffer overflow? What's the harm?
17. What is the difference between paging and segmentation?
18. The concept of physical address, logical address and virtual memory
19. What are the page replacement algorithms?
20. Tell me about your understanding of dynamic link libraries and static link libraries?
21. What is the difference between an external interrupt and an exception?
22. How much can you tell the complete process of a program from start to finish?
23. What is user mode and kernel mode
24. How to switch between user mode and kernel mode?
25. How the process terminates
26. Daemons, Zombies, and Orphans
27. How to avoid zombie process?
28. Introduce several typical locks?
29. Common memory allocation memory errors
30. In memory swap, where is the swapped out process stored?
31. How are atomic operations implemented?
32. Do you know what jitter is? It is also called bump phenomenon
11. Message Queue and Distributed 26 Channels
1. What is the basic function of message queue?
2. What are the advantages and disadvantages of message queues?
3. How to ensure the high availability of the message queue?
4. How to ensure that messages are not repeatedly consumed? In other words, how to ensure the idempotency of message consumption?
5. How to ensure the reliable transmission of messages? In other words, how to deal with the problem of message loss?
6. How to ensure the sequence of messages?
7. A large number of messages are backlogged in MQ for a long time, how to solve it?
8. What should I do if the message in MQ expires?
9. What are the important roles of RabbitMQ?
10. What are the important components of RabbitMQ?
11. How many broadcast types does RabbitMQ have?
12. Can Kafka be used independently of zookeeper? Why?
13. How many data retention strategies does Kafka have?
14. What are the partition strategies of Kafka?
15. Tell me about your understanding of Zookeeper?
16. What functions does Zookeeper have?
17. Tell me about your understanding of the ZAB protocol?
18. How does Zookeeper ensure the state synchronization of the master and slave nodes?
19. How many deployment modes does Zookeeper have?
20. Tell me about the notification mechanism of Zookeeper?
21. Why is there a master node in the cluster?
22. There are 3 servers in the cluster, and one of the nodes is down. Can Zookeeper still be used at this time?
23. Tell me about the process of two-phase commit and three-phase commit? What's the problem respectively?
24. How to deal with Zookeeper downtime?
25. What are the four types of data node Znode?
26. What is the relationship between Zookeeper and Dubbo?
Well, this is the end of this article, and I have compiled the answers to all the above questions into a PDF
