Welcome attention to micro-channel public number: architecture thousand words of notes Murong. Welcome attention to progress together.
Current salary levels between the first-tier cities 13 to 40k, but looking for a job is not just to have work experience on the line, but also requires a certain expertise. If you're more ambitious, you want to enter the US Mission Ali headlines and so these manufacturers, then it requires more expertise. So, three years of work experience in a Java programmer to have the knowledge of what it should be?
I found that after finishing the programmers need to understand a lot of knowledge.
First, project experience
Programmers project experience is the most important asset, but also the interview will ask questions. The interviewer will usually experience through projects to examine communication skills and ability to think candidates. Programmers usually three years of work experience in more than two project experience, but most of our cases are actually doing a function or a module of the product. Although we did a good job requirements, but for this interview is definitely not enough. For the interview, we have to complete the following four points.
- The project is in the end you know what to do, what function.
- Do you know the location and function of the project fits into the overall project and can clearly articulate calls between modules.
- We know the overall structure of your project and to the use of middleware, middleware and principles have a certain understanding.
- Fluent exposition complex problem themselves had in the project.
Two, Java basics
Technical knowledge of this interview is still quite common. But most asked is relatively simple. This is something I have been asked questions I listed, I refer to in private.
- The difference between stacks and queues
- The difference between abstract classes and interfaces
- Int and Integer difference between automatic and unpacking / packing-related issues
- Constant pool-related issues
Third, the Collections Framework
A set of underlying principles of the framework, the interview is a very common problem. Whether the interview to large companies, small companies or to interview would ask. Just ask asked shallow deep differences.
- Underlying ArrayList, LinkedList, HashMap, LinkedHashMap, ConcurrentHashMap implementation principle
- The difference between version 1.7 and version 1.8 of HashMap
- HashMap can not sort? Why length HashMap If a power of 2?
But anyway, we go to the interview, then, should the above-mentioned problems as much as possible to understand. The minimum requirement is to understand the underlying principles of hashmap.
Fourth, multi-threaded
- Creating ways threads? Wait, sleep, respectively, who approach the difference? Communication between threads?
- What is the introduction to a deadlock, deadlock met you? How do you troubleshoot. (Possible investigation by jps)
- Several ways to create a thread pool, thread pool do any good.
- Thread difference between inheritance and interface, the interface any good.
- Difference Synchronized, Lock, ReentrantLock, usage and principle.
- ThreadLocal usage and principles
- The role and principles Volatile keyword
- Optimistic and pessimistic locking
- Fair lock, lock unfair reentrant lock, spin locks, read locks appreciated
- What is the underlying principle of CAS and
- ArrayBlockingQueue, LinkedBlockingQueue, SynchronousQueue appreciated queue congestion etc.
- Incoming parameters and the inner workings of ThreadPoolExecutor
- Give you a specific business scenario, let you use ThreadPoolExecutor create a suitable thread pool
- Distributed environment, how to ensure the security thread
Multithreading is usually the focus of a senior programmer in an interview. Now a lot of projects of high concurrency, multithreading so this interview is still a lot of. Generally manufacturers will ask very deep. Tenth point from the beginning quite difficult, and we can learn, as appropriate, according to their own situation.
Five, JVM-related issues
- JVM memory mechanism
- Garbage collection mechanism introduced under which garbage collection algorithm, their characteristics
- Talk GC, talk about the Major GC, FullGe difference, what they have differences garbage collector?
- OutOfMemeryError this error you encountered? How do you solve handled?
- JVM tuning parameters which, at introduction, the online environment, how do you see the parameters of JVM and tuning?
- Can you write a class named java.lang.String (class loading process, parent delegation model)
- JVM this has been the focus of senior programmer interview. Want high salaries got to understand this. And not only understand, but also to have some practical experience.
Six framework related issues
- Spring with what design patterns? Spring bean injection of way? Understanding of SpringIOC and SpringAOP of?
- Spring transaction isolation level and propagation mechanisms?
- Difference Mybatis caching mechanism (cache and secondary cache), Mybatis file of mapper and $ # of
- SpringMVC process
- Spring and SpringBoot difference?
- Understanding of SpringBoot
- What are their differences RPC framework?
- Dubbo use and understanding
- Spring Cloud use and components, talk about your understanding
This framework has been the focus of the interview, but in my experience, this framework is generally not ask deep, rarely encountered make you say the source code, mainly examine your process and framework for understanding the design of the frame.
Seven, messaging middleware
- How is your company's messaging middleware technology selection?
- How to ensure high availability messaging middleware?
- How to ensure repeat messaging middleware to send a message?
- Message Queue has a significant backlog of messages, how can you deal with?
- How to ensure consumer spending news is in order?
- Allows you to develop a messaging middleware, how would you architecture?
Messaging middleware is still very important, both for work or who are the focus of the interview. It must be more research on this, to know more about.
Eight, Redis
- Why your company should use Redis? There are several Redis data types?
- Redis persistence mechanism? Redis expiration policy?
- How to ensure the availability of Redis?
- What is Cache penetrate? How to avoid? What is Cache avalanche? How to avoid?
- How to ensure that double buffering and write database consistency?
- Redis single-threaded model principle, why can support high-concurrency?
- Understand the underlying principles and architecture of Redis Sentinel
Now more and more high concurrency scenarios, the basic interview will ask cache, or just deep or shallow it. More often I ask is 1 to 6 and 7 may want to challenge manufacturers to study.
Nine, database
- Work is how you optimize the sql?
- In any case, the index will fail?
- Database storage engines, such as: MySQL's MyISAM and InnoDB difference?
- Leftmost principle index
- The underlying principle of the index
- The company is how you divide library sub-table? Sub-library sub-table program
Database optimization usually ask, involving local index will ask more, will be asked to use a relatively high degree of difficulty library sub-table, there are online programs, usually from the main library or Mycat, you can go to learn about a bit.
X. Other
- Distributed Transaction is how to solve?
- Distributed session program?
- Design a spike scene
- How to prevent multiple submissions form
- Linux basic operation command
- ElasticSearch of use and principles
- Zookeep of use and principles
This is mainly to ask you some common business scenarios, more open, but also to ask your own resume. For example, you resume the project which has ElasticSearch, then the interviewer will ask you to use these principles and middleware. If you successfully passed all the technical, then congratulations, you receive an offer from the infinitely close.
Micro-channel public number: architecture thousand words of notes Murong. Welcome attention to progress together.