I have been in Ali for four years and now I am P6. I feel that I have encountered a bottleneck. P7 has been unable to get on, so I will definitely try to change my job to Byte

Interview preparation

Both school and social recruitment can not avoid all kinds of interviews, written tests, how to prepare for these things is particularly important. After strategizing, win thousands of miles away! Instead of being unprepared, I think you can prepare for the interview from the following aspects:

1. Introduce yourself. (Introduce your project experience and some special skills rather than simply introducing yourself like, etc.)

**2. What knowledge points may be involved in your interview, and which knowledge points are the key points.

3. What questions are often asked in an interview and how should you answer them?

4. How to write your resume.

The remark that “80 per cent O ffer is in the hands of 20 per cent of the population” is not without reason. Strength offer offer does play a large part in determining your interview success, but for mood, or bad luck, there is still no satisfactory offer. Luck aside, take the mentality, do not be discouraged or doubt your ability because of the failure of the interview, after the failure of the interview to sum up the reasons for the failure, you will find yourself more and more powerful.

In addition, it is important to make clear that:

1. Be careful about what you write on your resume. This is likely to be the place where the interviewer will ask a lot of questions.

2. It is important to present your project experience well.

Common interview questions and their scope are as follows

Java based

1. The difference between overloading and overwriting
2. What’s the difference between a String and a StringBuffer or a StringBuilder? Why is String immutable?
3. Automatic packing and unpacking
4. = = and equals
5. The final keyword
6. Common methods of the Object class
7. Exception handling in Java
8. Get two common methods of keyboard input
9. What is the difference between interfaces and abstract classes

Collections framework

1. Arraylist is similar to LinkedList
2. ArrayList is different from Vector
3. The underlying implementation of HashMap
4. Difference between HashMap and Hashtable
5. Why is the length of a HashMap a power of 2
6. HashMap multithreading causes an infinite loop
7. HashSet is different from HashMap
8. ConcurrentHashMap and Hashtable
9. ConcurrentHashMap Thread-safe implementation/low-level implementation

Multithreading and concurrency

1. AQS principle
2. The way AQS shares resources
3. The underlying AQS uses the template method pattern
4. Talk about what you know about synchronized
5. Describe how you use the synchronized keyword. Did you use it in your project
6. Talk about the underlying principles of synchronized
7. Describe the underlying optimization of synchronized keyword after JDK1.6. Can you introduce these optimization in detail
8. Talk about the difference between synchronized and ReenTrantLock
9. Talk about the difference between the synchronized keyword and the volatile keyword
10. Why thread pools?
11. Implement the difference between Runnable interface and Callable interface
12. What is the difference between the execute() method and the submit() method?
13. How do I create a thread pool
14. Introduce the Atomic Atomic class
15. What are the four atomic classes in JUC packages?
16. Talk about the use of AtomicInteger
17. Can you give me a brief introduction to the AtomicInteger class

JVM

1. Is there a memory leak in Java?
2. Describe how the JVM loads Class files.
3. What is the Tomcat class loading mechanism?
4. Class loader parent delegate model mechanism?
5. Garbage collection FaQs
6. What is the GC? Why GC?
7. What is the Java garbage collection mechanism?
8. How do you tell if an object is alive?
9. What are the advantages and principles of garbage collection and consider 2 recycling mechanisms?
10. What are the methods of garbage collection in Java?
11. Describe your understanding of performance evaluation and test metrics?
12. What are the common performance tuning methods?

Network programming and operating systems

1. TCP and UDP are different
2. The process of entering a URL address in a browser ->> displaying the home page
3. The relationship between various protocols and the HTTP protocol
4. HTTP long connection and short connection
5. TCP Three handshakes and four waves (frequent interviewers)
6. A quick introduction to the Linux file system?
7. Some common Linux commands?

MySQL

1. What is your understanding of two common storage engines for MySQL: MyISAM and InnoDB?
2. Database index?
3. Why do indexes speed up queries?
4. Mysql > add index to table;
5. For large table common optimization means to say?

Spring

1. Scope of the Spring Bean
2. Isolation level in Spring transactions
3. Transaction propagation behavior in Spring transactions
4. What is AOP?
5. What is IOC?

distributed

1. Why redis cache?
2. Why redis and not Map/Guava?
3. The difference between Redis and memcached?
4. Redis common data structure and usage scenario analysis? (String, Hash, List, Set, Sorted Set)
5. Redis sets the expiration time
6. Redis memory flushing mechanism (MySQL has 2000W data, redis only 20W data, how to ensure that redis data is hot data?)
7. Redis persistence mechanism (how to ensure that redis hangs and then restarts data can be recovered)?
8. Redis transactions
9. Cache avalanche and cache penetration solutions
10. How to solve the Redis concurrent competing Key problem
11. How to ensure data consistency between the cache and the database in dual write?
12. What is a message queue? Why message queues?
13. Improve system performance through asynchronous processing (peak shaving, reduced response time)
14. Reduce system coupling
15. There are some problems with using message queues
16. JMS two message models
17. JMS five different message body formats
18. Common message queue comparison
19. What is the Dubbo? Why Dubbo?
20. What is the RPC? What is the principle of RPC?
21. How does Dubbo work?
22. Explain what load balancing is.
23. Look at Dubbo’s load balancing strategy?
24. Is ZooKeeper down and directly connected to Dubbo?

experience

1. Be careful about what you put on your resume. Be very familiar with what you put on your resume. Because most of the time, the interviewer will ask based on your resume;

2. It’s also important to have a project that’s on the table. This is likely to be an area where interviewers will ask a lot of questions, so take a good look at the projects you’ve worked on before the interview;

3. Talk to the interviewer about basic knowledge, such as the use of design patterns, the use of multi-threading, etc., based on specific project scenarios or how you use them in daily life;

4. It is recommended to find out in advance what the values of the company are and determine if you would be a good fit.

In addition, I personally feel that the interview is also like a brand new journey, failure and victory are common. Therefore, I advise you not to lose heart and morale because of the failure of the interview. Don’t be complacent because you passed the interview, you will be a better future, continue to work hard!

The last

Based on the knowledge of the system knowledge map above, I summarized the Internet company Java programmer interview questions and answers involved in the vast majority of the interview documents and architecture video materials to share with you free (including Dubbo, Redis, Netty, ZooKeeper, Spring Cloud, distributed, high concurrency and other architecture technology information), I hope to help you review before the interview and find a good job, but also save the time to study on the Internet to search for information, you can also pay attention to me later will have more dry goods to share.

PDF+ Spring100 + design pattern