The Internet’s cold winter has already begun, and such a strange scene has appeared in the entire industry: On the one hand, companies are speeding up the replacement of generations and increasing the pressure of internal competition to improve efficiency; on the other hand, they are recruiting people crazy, and the scarcity of talents is still extremely high. Demand.
Presumably everyone has a personal experience. The company's internal promotion requirements have become higher, the number of places has decreased, the requirements for external opportunities have also increased, and the increase and ranks have been restricted. The same is true abroad: Facebook, Microsoft, and Google have news of senior executives leaving from time to time.
Judging from the current environment, the difficulty of successful job-hopping is much higher than in previous years. An obvious feeling: This year's interview, both on one side and on the other, tested the technical skills of Java programmers.
These architecture technologies are compiled and hoped to have some reference to Java development friends and avoid detours. The focus of this article is whether you have gained and grown, and the rest is not important. I hope readers can remember this!
One, Java basics
- What are the characteristics of object-oriented?
- What is the difference between int and Integer?
- What is Math.round(11.5)? How much is Math.round(-11.5)?
- Programming question: Use the most efficient method to calculate what is 2 times 8 equal?
- Does the array have a length() method? Does String have a length() method?
- Can the constructor be overridden?
- Is it possible to inherit the String class?
- When an object is passed as a parameter to a method, the method can change the properties of the object and return the changed result. So, is it passed by value or by reference?
- What is the difference between String and StringBuffer?
- The difference between String, StringBuffer and StringBuilder.
- The difference between Overload and Override. Can overloaded methods be distinguished based on the return type?
- Describe the principle and mechanism of JVM loading class files?
- Can the interface be implemented by methods?
- Is it possible to call a non-static method from within a static method?
- What is GC? Why is GC?
- 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?
- Can a ".java" source file contain multiple classes (not inner classes)? What are the restrictions?
- What are the uses of the final keyword in Java?
- Encoding conversion: How to convert GB2312 encoded string to ISO-8859-1 encoded string?
- What is the difference between error and exception?
- There is a return statement in try{}, so will the code in finally{} immediately after this try be executed, when is it executed, before or after return?
- Do List, Set, Map inherit from Collection interface?
- Tell me about the storage performance and characteristics of ArrayList, Vector, LinkedList?
- The difference between HashMap and Hashtable?
- What is the difference between Arraylist and Vector?
- What are the characteristics of the three interfaces of List, Map, and Set when accessing elements?
- What is the difference between sleep() and wait()?
- When a thread enters a synchronized method of an object, can other threads enter other methods of this object?
- There are several ways to implement multithreading, what are they? There are several ways to implement synchronization, and what are they?
- After a thread enters the synchronized method A of an object, can other threads enter the synchronized method B of this object?
- Briefly describe the similarities and differences between synchronized and java.util.concurrent.locks.Lock?
- How many ways are there to write multithreaded programs?
- How to implement serialization in Java and what's the point?
Java basic interview question bank and learning mind map
Second, the database
- Explain the steps of JDBC operating database.
- How to improve the performance of reading data when using JDBC to operate the database? How to improve the performance of updating data?
- In database programming, what is the role of connection pool?
- What is the ACID of a transaction?
- Talk about dirty reading, phantom reading and non-repeatable reading?
- How to deal with transactions in JDBC?
- What are the ways to obtain the class object of a class?
- What are the built-in objects of JSP? What are the roles?
- The difference between get and post request?
- Explain the four scopes in JSP.
Database interview question bank and learning mind map
Three, SSM framework
- What is the difference between using # and $ to write placeholders in MyBatis?
- Explain the role of namespace in MyBatis.
- What are IoC and DI? How is DI implemented?
- Explain what is called AOP (Aspect Oriented Programming)?
- How do you understand the concept of "crosscutting attention"?
- How do you understand the concepts of Joinpoint, Pointcut, Advice, Introduction, Weaving, and Aspect in AOP?
- What types of transaction management does Spring support? Which method do you use in the project?
- How does Spring MVC work?
- What is an XSS attack?
- SQL injection attack?
- What is a CSRF attack?
SSM interview question bank and learning mind map
Four, redis
- What are the benefits of using redis?
- What data structure does Redis have?
- If there are a large number of keys that need to be set to expire at the same time, what should generally be noted?
- Why does Redis need to put all data in memory?
- What kinds of persistence methods does Redis provide?
- How to choose a suitable persistence method?
- Which java client have you used for redis support?
- What is the master-slave replication model of Redis cluster?
- How is replication between Redis clusters?
- How to test the connectivity of Redis?
Interview question bank and learning mind map
Five, message queue
- Why use message queues?
- What are the disadvantages of using message queues
- Why choose RocketMQ; the difference between RocketMQ and ActiveMQ
- How does RocketMQ ensure the high availability of the system?
- The message middleware cluster crashes, how to ensure that millions of production data are not lost?
Message queue interview question bank and learning mind map
六、spring boot
- What are the core configuration files of Spring Boot? What is the difference between them?
- What are the formats of Spring Boot configuration files? What is the difference between them?
- What is the core annotation of Spring Boot? Which annotations are mainly composed of?
- What are the ways to enable Spring Boot features?
- Does Spring Boot need a separate container to run?
- How to run some specific code when Spring Boot starts?
- What are the ways to read configuration in Spring Boot?
- How does Spring Boot define multiple sets of different environment configurations?
- How to implement timing tasks in SpringBoot?
- How do we connect to an external database like MYSQL or orcale?
Spring Boot interview question bank and learning mind map
七、spring cloud
- What is a microservice
- How do microservices communicate independently. What are the differences between Spring Cloud and Dubbo?
- How does springcloud realize service registration and discovery
- The difference between Ribbon and Feign
- The role of springcloud circuit breaker
- How does springcloud realize service registration and discovery
- What are the components in springcloud?
Spring Cloud Interview Question Bank
8. Other
- The difference between cookie and session
- A complete http request process
- Talk about long connections
- How does TCP guarantee reliable transmission?
- The difference between URI and URL
- The difference between http and https?
- Docker commonly used commands
- What is a Docker image?
- What is a Docker container?
- What is Docker Hub?
- What is Git fork (fork)? What is the difference between fork, branch and clone?
- What is the difference between "git pull" and "git fetch"?
- What are the advantages and disadvantages of using Ajax?
- Cross-domain issues, who restricts cross-domain issues, and how to solve them
to sum up
Opportunities are always reserved for those who are prepared! The editor will share the eight types of interview questions and answers, study notes, and Xmind mind maps, such as Java basics + database + SSM framework + Redis + message queue + Spring Boot + Spring Cloud, which have been sorted out above.