Preface
What are the job requirements for a java development position with a monthly salary of 30K? What do you ask in the interview?
Job requirements: 1. Bachelor degree (or above) in computer or related majors, with more than 3 years of experience in Java server development, familiar with commonly used Java open source frameworks, such as Spring, SpringMVC, SpringBoot, Hibernate, MyBatis, etc., to understand its principles and Implementation mechanism;
2. Good at Java Web service development, familiar with various Web application development modes, with rich experience in high concurrency and big data system design, R&D, and debugging is preferred;
3. Proficient in Java and object-oriented design and development, familiar with Common design patterns, system design experience, excellent open source software source code research and experience is preferred;
4. Familiar with the principles and use of common databases (MySQL, Redis, etc.), have good database design capabilities, and have SQL writing and optimization Rich experience;
5. Familiar with Linux operating system and master commonly used Shell commands;
Based on these requirements, we as programmers must master:
1. Data structure and algorithm. You should master simple algorithms and data structures? Is this request too much? As a programmer, if you don’t even understand the two basic structures of arrays and linked lists, what can you expect to understand? Balanced binary trees, red-black trees, hash tables, heaps, buckets, graphs, and more. For complex data structure? Simple bubbling and selection sorting is a difficult master in handwriting. I also expect him to have heard of fast sorting, inserting, hill, heap sorting, two-way merge, multi-way merge, bucket sorting, counting, cardinal numbers, these should be mastered Something very basic? Sometimes people who know the complexity of time and space are Amitabha...
2. Operating system. How many basic linux commands do you have to know? Should you still have a little bit of the basic concepts of memory allocation, process, and thread scheduling? Not to mention that these things are useless. Many softwares refer to the design ideas of many operating systems when they are implemented.
3. The database level. Understand the definition of several major paradigms. Can you always understand the ACID of database transactions? Do you have to know the strength of the isolation levels and the remaining problems? Some people have been working for several years, not too much? Have you ever done SQL optimization? The difference between the mainstream MYSQL storage engines, the difference between several indexes and the application scenarios, should be as familiar as many? As a technical dog, you should know something about the implementation of database transactions, right? Do you know the two-phase submission and the three-phase submission? How much you know depends on your personal depth.
The above is a general level thing, as long as you say you are a programmer, you should know. Now let's break down the things related to java.
The 30K interview will definitely ask: performance optimization, microservice architecture, concurrent programming, open source framework, distributed, etc. The following will analyze these points.
The total number of pages of the complete set of materials is 946 pages, the method of obtaining: forwarding + forwarding + after forwarding, the backstage private message keyword "interview" is obtained and received
Performance optimization
- tomcat performance optimization
- JVM performance optimization
- Mysql performance optimization
1. Tomcat performance optimization
- How do you tune Tomcat?
- How to increase the number of Tomcat links?
- How to increase the memory of Tomcat?
- How to disable files in listed directories in Tomcat?
- How many ways to deploy Tomcat?
- Tomcat optimization experience sharing?
- .........
2. JVM performance optimization
- JVM class loading process?
- JVM memory allocation?
- Describe the principle and mechanism of JVM loading Class files?
- What is GC? Why is there a GC?
- Briefly describe the Java garbage collection mechanism?
- How to judge whether an object is alive? (How to determine GC objects)
- The advantages and principles of garbage collection. And consider 2 recycling mechanisms?
- 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?
- Will there be a memory leak in Java? Please describe briefly.
- Deep copy and shallow copy
- What will System.gc() and Runtime.gc) do?
- finalize (when is the method called? What is the purpose of finalization?
- If the object reference is set to null, will the garbage collector immediately release the memory occupied by the object?
- What is distributed garbage collection (DGC)? How does it work?
- What is the difference between a serial collector and a throughput collector?
- In Java, when can an object be garbage collected?
- Briefly describe Java memory allocation and recovery strategies, Minor GC and Major GC.
- Will garbage collection occur in the permanent generation of the JVM?
- What are the methods of garbage collection in Java?
- What are class loaders and what are the class loaders?
- Class loader parent delegation model mechanism?
- ...........
Microservice architecture
- SpringCloud
- SpringBoot
- Dubbo
1. SpringCloud interview finishing
- What is Spring Cloud?
- What are the advantages of using Spring Cloud?
- What does service registration and discovery mean? How does Spring Cloud implement it?
- What is the significance of load balancing?
- What is Hystrix? How does it achieve fault tolerance?
- What is a Hystrix circuit breaker? Do we need it?
- What is Netflix Feign? What are its advantages?
- What is Spring Cloud Bus? Do we need it?
- ..............
2. SpringBoot interview finishing
- What is Spring Boot?
- What are the advantages of Spring Boot?
- What is JavaConfig?
- How to reload changes on Spring Boot without restarting the server?
- What is a monitor in Spring Boot?
- How to disable Actuator endpoint security in Spring Boot?
- How to run Spring Boot application on a custom port?
- What is YAML?
- How to achieve the security of Spring Boot applications?
- How to integrate Spring Boot and ActiveMQ?
- How to use Spring Boot to implement paging and sorting?
- What is Swagger? Have you implemented it with Spring Boot?
- What are Spring Profiles?
- What is Spring Batch?
- What is a FreeMarker template?
- How to use Spring Boot to implement exception handling?
- Which starter maven dependencies did you use?
- What is a CSRF attack?
- What is WebSockets?
- What is AOP?
- What is Apache Kafka?
- How do we monitor all Spring Boot microservices?
- ......
3. Dubbo interview finishing
- Zookeeper in Dubbo acts as the registry. If the registry clusters are all down, can publishers and subscribers still communicate?
- Dubbo service load balancing strategy?
- How does Dubbo solve the security mechanism
- The difference between dubbo registration center and direct connection
- .........
Concurrent programming advanced interview
- Have you used Synchronized and what is its principle?
- You just mentioned acquiring a lock on an object. What exactly is this "lock"? How to determine the lock of an object?
- What is reentrancy, and why is Synchronized a reentrant lock?
- What optimizations has JVM made to Java's native locks?
- Why is Synchronized an unfair lock?
- What is lock elimination and lock coarsening?
- Why is Synchronized a pessimistic lock? What is the realization principle of optimistic lock? What is CAS and what are its characteristics?
- Is optimistic locking necessarily good?
- Compared with Synchronized, what is the difference in the implementation principle of ReentrantLock?
- So please talk about the AQS framework?
- Please compare the similarities and differences between Synchronized and ReentrantL ock in as much detail as possible.
- How does ReentrantLock achieve reentrancy?
- In addition to ReetrantL ock, which concurrency tools in JUC have you been exposed to?
- Please talk about ReadWriteLock and StampedLock.
- How to synchronize Java threads with each other? What synchronizers do you know about? Please introduce them separately.
- CyclicBarrier and CountDownl _atch look very similar, please compare?
- How is the thread pool implemented in Java?
- Several core construction parameters for creating a thread pool?
- How are the threads in the thread pool created? Are they created at the beginning of the thread pool?
- Since it is mentioned that different thread pools can be created by configuring different parameters, what are the default thread pools implemented in Java? Please compare their similarities and differences.
- How to submit threads in Java thread pool?
- What is Java's memory model and how do threads in Java see each other's variables?
- Please talk about the characteristics of volatile and why it can guarantee the visibility of variables to all threads?
- Since volatile can guarantee the visibility of variables between threads, does it mean that operations based on volatile variables are concurrently safe?
- Please compare the similarities and differences between volatile and Synchronized.
- Please talk about how ThreadLocal solves concurrency safety?
- Many people say that ThreadLocal should be used with caution, talk about your understanding, what should be paid attention to when using ThreadLocal?
- ..........
Open source framework interview
- Spring interview finishing
- SpringMVC interview finishing
- MyBatis interview finishing
1. Spring interview finishing
- What is the Spring Framework? What are the main modules of the Spring Framework?
- What are the benefits of using the Spring framework?
- What is inversion of control (IOC)? What is dependency injection?
- Please explain the LOC in the Spring framework?
- What is the difference between BeanFactory and ApplicationContext?
- How many ways to configure Spring?
- How to configure Spring based on XML configuration?
- How to configure Spring in a Java-based configuration?
- How to configure Spring with annotations?
- Please explain the life cycle of Spring Bean?
- What is the difference between the scope of Spring Bean?
- What are Spring inner beans?
- Are singleton beans in the Spring framework thread-safe?
- Please give an example of how to inject a Java Collection in Spring?
- How to inject a Java.util.Properties into Spring Bean?
- Please explain the autowiring of Spring Bean?
- Please explain the difference in auto-assembly mode?
- .......
2. SpringMVC interview finishing
- What is SpringMVC?
- Advantages of Spring MVC:
- How does SpringMVC work?
- SpringMVC process?
- Is SpringMvc's controller a singleton mode? If so, what is the problem and how to solve it?
- If you have also used struts2, what are the differences between springMVC and struts2?
- The comment of the controller in SpingMvc generally uses that. Is there any other comment that can be substituted?
- What is the effect of @RequestMapping annotation on classes?
- How to map a request to a specific method?
- If in the interception request, I want to intercept the method submitted by the get method, how to configure it?
- How to get Request or Session in the method?
- I want to get the parameters passed in from the foreground in the interception method, how do I get it?
- If there are many parameters passed in at the front desk, and these parameters are all an object, how to quickly get this object?
- What is the return value of the function in SpringMvc?
- How does Spring MVC set up redirection and forwarding?
- What object does SpringMvc use to transfer data from the background to the foreground?
- There is a class in SpringMvc that merges views and data together, what is it called?
- How to put the data in ModelMap into Session?
- How do SpringMvc and AJAX call each other?
- How is the interceptor written in SpringMvc
- ......
3. MyBatis interview finishing
- What is MyBatis?
- Talk about the cache of MyBatis
- How does Mybatis perform paging? What is the principle of the paging plugin?
- Briefly describe the operation principle of Mybatis plug-in, and how to write a plug-in?
- What does Mybatis dynamic SQL do? What are the dynamic SQL? Can you briefly describe the principle of dynamic SQL execution?
- What is the difference between #{} and ${}?
- Why is Mybatis a semi-automatic ORM mapping tool? What is the difference between it and fully automatic?
- Does Mybatis support lazy loading? If so, what is its implementation principle?
- What is the difference between MyBatis and Hibernate?
- What are the benefits of MyBatis?
- Briefly describe the mapping relationship between Mybatis's Xml mapping file and Mybatis internal data structure?
- What is the interface binding of MyBatis and what are the benefits?
- There are several ways to implement interface binding, how are they implemented?
- Under what circumstances are annotation binding and when xml binding?
- There are several ways to implement MyBatis-one for one-and how do they operate?
- Can Mybatis perform one-to-one and one-to-many related queries? What are the implementation methods and the differences between them?
- How is the dynamic Sql in MyBatis set? What syntax?
- How does Mybatis encapsulate the sql execution result as a target object and return it? What are the mapping forms?
- In the Xml mapping file, besides the common selectlinsertlupdae|delete tag, what other tags are there?
- When the attribute name in the entity class is not the same as the field name in the table, what if the query result is encapsulated in the specified pojo?
- In the Mybatis mapping file, if the A tag refers to the inside of the B tag through include
- In the mapping file, if the A tag refers to the content of the B tag by including in the mapping file, can the B tag be defined after the A tag, or must it be defined before the A tag?
- What are the core processing classes of IBatis and MyBatis?
- ......
Distributed interview
- Distributed current limiting interview finishing
- Distributed communication interview collation
- Distributed database interview finishing
1.1, ZooKeeper interview topics
1.2, Nginx interview topics
2.1, RabbitMQ message middleware interview topic
2.2, Kafka interview topic
3.1, Redis interview topic
3.2, MongoDB interview topics
3.3, memcached interview topic
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method of obtaining
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