Job hopping happens all the time, but I suggest you think about why you want to jump ship before you do. Must not follow the trend, see colleagues one by one to go, oneself also blindly start the interview up (during the period was not fully prepared), is it because of technical reasons (affect their own development, offset their own planning track), or less money, not appreciated.

Poorly prepared interviews are a waste of time and irresponsible (if your title is high, forget it).

Today, I’m going to share with you the Java interview outline that Chenssy has compiled for this job change. Most of them are interview questions, which can be used to fill in the gaps. Of course, there is no way to cover all the questions listed here.

Project introduction

Most of the time, this is the opening question in an interview, and the interviewer asks this question to measure your overview skills and overall vision. Some people often complain that they are piling up business every day but not growing. In fact, in many cases the heap business does exist, but it is not without growth. It is not middleware or technical architecture that is growth. For example, our demand analysis ability, communication and collaboration ability, product thinking ability and abstract modeling ability are all very important hard strengths.

Okay, let’s move on to the main text.

1. Define what the project does. 2. (Why did you do this project, what pain points did it address, and what value did it bring?) 3. Define the function of the project. (What features are involved in this project?) 4. Define the technology of the project. What technologies are used in this project? 5. Define the position and role of individuals in the project. What was your role in the project? 6. Define the overall structure of the project. 7. Identify the strengths and weaknesses of the project and how you would redesign it. 8. Identify highlights of the project. (What are the highlights of this project?) 9. Identify technical growth. (What technical growth did you experience through this project?)

Java based

A HashMap is thread-safe and is not thread-safe. 5. What are the differences between HashMap 1.7 and 1.8? What are the optimizations for HashMap 1.8? Final Finally Finalize 7 Strong Reference, Soft reference, Weak reference, virtual reference 8 Java reflection 9 Array.sort implementation principle and Collection implementation principle 10 LinkedHashMap application Cloneable interface implementation principle 12, exception classification and handling mechanism 13, the difference between wait and sleep 14, how to allocate arrays in memory

Java concurrency

1. Realization principle of synchronized and lock optimization? 2. How does volatile work? Java semaphores? 4. The difference between synchronized and ordinary methods? 5. How to implement that all threads wait for an event to occur before executing it? 6, the CAS? What are the defects of CAS and how to solve them? 7. What’s the difference between synchronized and lock? 8, How to lock Hashtable? HashMap concurrency problem? 10, ConcurrenHashMap? Why red black trees in 1.8? How to detect deadlocks? How do I prevent deadlocks? 13. Java Memory Model? 14. How to ensure that i++ results are correct in multiple threads? What are the types, differences and usage scenarios of thread pools? Analysis of thread pool implementation principle and thread scheduling process? 17, how to tune the thread pool, how to confirm the maximum number? 18. What should we pay attention to when using the ThreadLocal principle? 19. What are the uses of CountDownLatch and CyclicBarrier and the differences between them? LockSupport tool 21. Condition interface and its implementation principle 22. Understanding of Fork/Join framework 23

Spring

BeanFactory and FactoryBean? 2. Understanding of Spring IOC and its initialization process? BeanFactory and ApplicationContext? How is the life cycle of Spring beans managed? 5. What is the loading process of Spring beans? 6. If you were asked to implement Spring AOP, how would you do it? 7. What issues would you pay attention to if you were asked to implement Spring IOC? How does Spring manage transactions? Transaction management mechanism? What are the different transaction propagation behaviors of Spring? What design patterns are used in Spring? How does Spring MVC work? How does Spring loop injection work? 13. Understanding Spring AOP, terms, how do they work with each other? 14. How does Spring secure Controller concurrency?

Netty

3, The thread model of Netty 4, TCP sticky/unpack causes and solutions 5, understand which serialization protocols? 6. Zero copy implementation of Netty 7. What are the high performance of Netty

Distributed correlation

1, 2, the underlying implementation principle and mechanism of Dubbo from release to describe a service consumed the detailed process of 3, distributed systems do service governance 4, the concept of interface idempotence 5 lost message middleware how to solve the problem. 6, Dubbo service request failed how processing 7, reconnection mechanism will not cause errors 9. How to achieve load balancing and what algorithms can achieve it? 10. What is the purpose of Zookeeper and the principle of election? 11. Vertical split and horizontal split of data. Zookeeper Watch mechanism 14, Redis/ZK node breakdown how to handle 15, distributed cluster how to achieve a unique sequence number 16, how to make a distributed lock 17, used MQ, how to use, What are the advantages and disadvantages compared with other MQ, MQ connection is thread safe 18, HOW to ensure that the data of MQ system is not lost 19, list you can think of database sub-table strategy; How can I solve the problem of querying all tables in different databases and different tables

The database

Mysql > alter table lock; mysql > alter table lock; mysql > alter table lock; What indexes are used for what situations 7. Transaction characteristics and isolation level

The cache

3, How to use Redis to achieve distributed lock 4, how to solve the problem of Redis concurrency competition 5, Redis persistence several ways, what are the advantages and disadvantages? Redis cluster, high availability, principle 8, Redis cache sharding 9, Redis data obsoletion strategy

JVM

When a memory leak occurs, the JVM can run out of memory. What are the criteria for progression from the younger generation to the older generation of the JVM? 5. FullGC occurs frequently in JVM. How to check problems online? 6. Why is the parent delegate pattern used for class loading? Are there any scenarios that break this pattern? Garbage collection (yGC), garbage collection (FGC), garbage collection (G1), garbage collection (CMS), garbage collection (G1) Stackoverflow error, Permgen space error

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