Foreword:
The title is not important, I don’t know whether you are bald or not; in order to organize this complete Java interview question, my hair curtain ~ hair curtain are almost gone! Assi, if you don't give me three consecutive years, I'm sorry for my hair. The article is somewhat dry, except for dry goods, it is dry goods; I still hope to help the majority of bald friends
Basics
1. What are the characteristics of the Java language
2. The difference between object-oriented and process-oriented
3. The size of the eight basic data types and their encapsulation classes
4. The naming rules of identifiers.
5. The role of the instanceof keyword
6, Java automatic boxing and unboxing
7. The difference between overloading and rewriting
8. The difference between equals and ==
9. The role of Hashcode
10. What is the difference between String, String StringBuffer and StringBuilder?
11. The difference between ArrayList and linkedList
12. The difference between HashMap and HashTable
13. Collection package structure, the difference with Collections
14. Four references to Java, strong and weak
15. Commonly used features of generics
16. How many ways does Java create objects?
17. Is it possible that two unequal objects have the same hashcode?
18. What is the difference between deep copy and shallow copy?
19.What are the uses of final?
20. What are the uses of static?
21. What is the return value of 3*0.1==0.3
22. Is there any difference between a=a+b and a+=b?
23. Try catch finally, there is return in try, is finally executed?
24, Excption and Error package structure
25. What situations have you encountered with OOM and SOF?
26. Briefly describe the basic concepts of threads, programs, and processes. And what is the relationship between them?
27.What are the basic states of threads?
28. What if some fields do not want to be serialized in Java serialization?
29, IO flow in Java
30, the difference between Java IO and NIO
31. The role of java reflection on the principle
32. Tell me about the difference between List, Set and Map?
JVM articles
1. Summary of knowledge points
2. Detailed knowledge points:
3. Class loading and unloading
4. Briefly describe the memory model of JVM-thread private area-thread shared area
5. The difference between heap and stack
6. When will FullGC be triggered
7. What is the Java virtual machine? Why is Java called a "platform-independent programming language"?
8. Java memory structure
9. Object allocation rules
10. Describe the principle and mechanism of JVM loading class files?
11. Java object creation process
12. Class life cycle
13. Briefly describe the object structure of Java
14. How to judge the object can be recycled?
15. Will garbage collection occur in the permanent generation of the JVM?
16. Garbage collection algorithm
17. What are the tuning commands?
18. Tuning tools
19. When do Minor GC and Full GC occur respectively?
20. Which JVM performance tuning do you know
Multithreading & Concurrency
1. There are several ways to implement multithreading in Java
2. How to stop a running thread
3. What is the difference between notify() and notifyAll()?
4. What is the difference between sleep() and wait()?
5. What is volatile? Can order be guaranteed?
6. What is the difference between the start() and run() methods in the Thread class?
7. Why wait, notify and notifyAll are not in the thread class?
8. Why should the wait and notify methods be called in a synchronized block?
9. What is the difference between interrupted and isInterruptedd methods in Java?
10. What is the difference between synchronized and ReentrantLock in Java?
11. There are three threads T1, T2, T3, how to ensure sequential execution?
12. What is the difference between SynchronizedMap and ConcurrentHashMap?
13. What is thread safety
14. What is the function of the yield method in the Thread class?
15. What is the difference between submit() and execute() methods in Java thread pool?
16. Talk about your understanding of the synchronized keyword
17. Tell me how I use the synchronized keyword. Have you used the synchronized keyword in your project? There are three main ways to use the synchronized keyword:
18. What is thread safety? Is Vector a thread safe class?
19. The role of the volatile keyword?
20. What are the commonly used thread pools?
21. Briefly describe your understanding of thread pools
22. How is the Java program executed?
Spring
1. Spring's IOC and AOP mechanism?
2. What is the difference between Autowired and Resource keywords in Spring?
3. There are several ways of dependency injection and what are each?
4. Tell me what is Spring
5. Spring MVC process
6. How does SpringMVC set redirection and forwarding?
7. What are the annotations commonly used in SpringMVC?
8. Spring's AOP understanding:
9, Spring's IOC understanding
10. Explain the life cycle of spring bean
11. Explain the scope of several beans supported by Spring.
12. Spring has several ways to inject beans based on xml:
13. What design patterns are used in the Spring framework?
MyBatis articles
1. What is MyBatis
2. The advantages and disadvantages of MyBatis
3. What is the difference between #{} and ${}?
4. What should I do when the attribute name in the entity class is different from the field name in the table?
5. How does Mybatis pagination? What is the principle of the paging plugin?
6. How does Mybatis encapsulate the sql execution result as a target object and return it? What are the mapping forms?
7. How to perform batch insert?
8. In the Xml mapping file, besides the common select|insert|updae|delete tags, what other tags are there?
9. There are several ways to realize one-to-one in MyBatis? How to operate?
10. Does Mybatis support delayed loading? If so, what is its implementation principle?
11. Mybatis's primary and secondary caches.
SpringBoot
1. What is SpringBoot? Why use SpringBoot
2. What is the core annotation of Spring Boot? Which annotations are mainly composed of?
3. What are the ways to run Spring Boot?
4. How to understand Starters in Spring Boot?
5. How to run some specific code when Spring Boot starts?
6. Does Spring Boot need a separate container to run?
7. What is the monitor in Spring Boot?
8. How to use Spring Boot to implement exception handling?
9. How do you understand Starters in Spring Boot?
10. What are the starters commonly used in springboot
11. How many ways does SpringBoot implement hot deployment?
12. How to understand the Spring Boot configuration loading sequence?
13. What are the core configuration files of Spring Boot? What is the difference between them?
14. How to integrate Spring Boot and ActiveMQ?
15. How to reload the changes on Spring Boot without restarting the server?
16. What is the difference between Spring Boot, Spring MVC and Spring?
17. Can you give an example to explain more of the contents of Statusers?
18. What other Starter Project Options does Spring Boot provide?
MySQL articles
1. What are the three paradigms of the database
2. What are the database engines?
3. The difference between InnoDB and MyISAM
4. Database transactions
5. Index problem
6, SQL optimization
7. Briefly talk about the difference between drop, delete and truncate
8. What is a view
9. What is inner join, left outer join, right outer join?
10.What are the problems caused by concurrent transactions?
11. What are the transaction isolation levels? What is the default isolation level of MySQL?
12. How to optimize large tables?
1. Limit the scope of the data
2. Read/write separation
3. Vertical partition
4. Horizontal Partition
13. After sub-database sub-table, how to deal with id primary key?
14. What are the mysql tables related to permissions?
15. What data types does mysql have
16. Three ways to create an index, delete an index
Redis articles
1. Redis persistence mechanism
2. Cache avalanche, cache penetration, cache warm-up, cache update, cache degradation, etc.
3. What are hot data and cold data
4. What are the differences between Memcache and Redis?
5. Why is single-threaded redis so fast?
6. The data types of redis and the usage scenarios of each data type
7. Redis expiration strategy and memory elimination mechanism
8. Why Redis is single-threaded
9. Common Redis performance problems and solutions?
10. Why is Redis's operation atomic and how to ensure atomicity?
11. Redis transaction
SpringCloud
1. What is SpringCloud
2. What is a microservice
3. What are the advantages of Spring Cloud
4. What is a service circuit breaker? What is service degradation?
5. Both Eureka and zookeeper can provide service registration and discovery functions. Could you please explain the difference between the two?
6. What is the difference between SpringBoot and SpringCloud?
7. What is the significance of load balancing?
8. What is Hystrix? How does it achieve fault tolerance?
9. What is Hystrix circuit breaker? Do we need it?
10. Talk about the implementation principle of RPC
Nginx articles
1. Briefly describe what Nginx is, and what advantages and functions does it have?
2. How does Nginx process an HTTP request?
3. List some Nginx features
4. Please list the differences between Nginx and Apache
5. In Nginx, how to use undefined server names to prevent requests from being processed?
6. Please explain what are the Master and Worker processes on the Nginx server?
7. Please explain the forward proxy and reverse proxy in the proxy
8. Explain the use of Nginx
MQ articles
1. Why use MQ
2. Advantages and disadvantages of MQ
3. What is the difference between Kafka, ActiveMQ, RabbitMQ, RocketMQ?
4. How to ensure high availability?
5. How to ensure reliable transmission of messages? What to do if the message is lost
6. How to ensure the order of messages
7. How to solve the problem of delay and expiration of message queue? What should I do when the message queue is full? There are millions of news backlogged for several hours, talk about how to solve it?
8. Ideas for designing MQ
Data structure and algorithm
1. Common data structure-1. Array-2. Stack-3. Queue-4. Linked list-5. Figure-6. Tree-7. Prefix tree-8. Hash table
2. There are {1,2,3,4,5,6,7,8,9} in the data, please randomly shuffle the order and generate a new array (please implement it in code)
3. Write the code to judge whether an integer is a power of 2 (please implement the code, and refuse to call the API method)
4. Assuming that today is Sunday, March 1, 2015, please work out the day of the week after 13 months and 6 days, and how many days are away from now (please use code to implement, decline to call API methods)
5. There are two baskets, A and B. Basket A contains eggs, and basket B contains apples. Please use object-oriented thinking to exchange items in the two baskets (please use code)
6. More algorithm exercises
Linux articles
1. What symbol is used to represent the absolute path? What is the current directory and upper directory? What is the main directory? What command is used to switch directories?
2. How to check the current process? How to perform exit? How to check the current path?
3. What commands are available for viewing files
4. List a few commonly used Linux commands
5. How do you usually check the log?
Resume
- Why is the resume important?
- Let’s start with the interview
- Let’s start with the interview
- Some things you must know
- Two rules that must be understood
- How to write project experience
- How to write professional skills
- Typographic considerations
- Some other small tips
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