1. Redis interview questions

1. What is Redis? .

2. Redis data type?

3. What are the benefits of using Redis?

4. What advantages does Redis have over Memcached?

5. What are the differences between Memcache and Redis?

Redis is single-process single-thread?

7. What is the maximum capacity of a string value?

8. What is the persistence mechanism of Redis? What are their strengths and weaknesses?

9. Redis Common performance Problems and solutions:

Delete redis expiration key?

11. Redis recycling strategy (elimination strategy)?

12. Why does EDis need to put all data in memory?

13. Do you know the synchronization mechanism of Redis?

14. What are the benefits of Pipeline? Why do we use Pipeline?

15. Have you used Redis cluster? What is the principle of cluster?

16. When will Redis cluster solution make the whole cluster unusable?

17, What are the Java clients supported by Redis? Which is the official recommendation?

18. What are the advantages and disadvantages of Jedis versus Redisson?

19. How to set and verify the password in Redis?

20, What about the Redis hash slot?

21. What is the master/slave replication model of Redis cluster?

Will Redis write operations be lost? Why is that?

23. How are Redis clusters replicated?

24. What is the maximum number of nodes in Redis cluster?

How to select database for Redis cluster?

26, How to test the connectivity of Redis?

27, How to understand Redis transaction?

What are the Redis transaction related commands?

29. How to set the expiration time and permanent validity of Redis key respectively?

30, How does Redis do memory optimization?

How does the Redis recycle process work?

32, What are some ways to reduce Redis memory usage?

What happens when Redis runs out of memory?

34, How many keys can a Redis instance hold? List, Set, Sorted Set How many elements can they store at most?

MySQL has 2000W data, redis only 20W data, how to ensure that the data in Redis is hot data?

What is the most suitable scene for Redis?

37. Suppose there are 100 million keys in Redis and 10W of them start with a fixed known prefix. What if you could find all of them?

38. If a large number of keys need to be set to expire at the same time, what should I pay attention to?

Have you ever used Redis for asynchronous queues? How do you use it?

Have you ever used Redis distributed lock? What is it?

2. Dubbo interview questions

1. What is Dubbo?

2. Why Dubbo?

What’s the difference between Dubbo and Spring Cloud?

4. What protocols are supported by Dubbo and which are recommended?

Does Dubbo need a Web container?

6. What service containers are built into Dubbo?

What types of node roles are there in Dubbo?

8. Draw a flowchart for service registration and discovery

What registry does Dubbo use by default? Any other options?

What are the configuration methods of Dubbo?

11. What are the configurations of the Dubbo core?

12. What are the Consumer properties that can be configured on the Provider?

13. What happens if the dependent service is unavailable when Dubbo starts?

14. What serialization framework does Dubbo recommend, and what else do you know?

15. What communication framework does Dubbo use by default? Any other options?

16. What cluster fault tolerance schemes does Dubbo have? Which is the default?

17. What load balancing strategies does Dubbo have and what is the default?

18, Registered multiple services of the same type, what if you test a specified service?

19. Does Dubbo support multi-protocol services?

20. What to do when a service interface has multiple implementations?

21. How can the service be compatible with the old version?

22. Can Dubbo cache results?

23. Are calls between Dubbo services blocked?

24. Does Dubbo support distributed transactions?

What does the Dubbo Telnet command do?

Is Dubbo support service degraded?

27. How does Dubbo stop gracefully?

28, What is the principle that service providers can achieve failure kick out?

29. How to solve the problem of long service invocation chain?

30. What are the recommended fault tolerance policies for service reads and writes?

31. What packages must Dubbo rely on?

32. What can Dubbo’s administrative console do?

33. Talk about the process of Dubbo service exposure.

34. Has Dubbo stopped maintenance?

What’s the difference between a Dubbo and a Dubbox?

36. What other distributed frameworks do you know?

Does Dubbo integrate with Spring Boot?

What are the problems encountered in the process of use?

Have you read the source code for Dubbo?

40. Do you prefer Dubbo or Spring Cloud?

3.Spring Boot Interview questions

1. What is Spring Boot?

2. What are the advantages of Spring Boot?

3. What is JavaConfig?

4. How do I reload changes on Spring Boot without restarting the server?

5. What is the monitor in Spring Boot?

6. How to disable THE security of endpoints in Spring Boot?

7. How to run a Spring Boot application on a custom port?

8. What is YAML?

How to implement Spring Boot application security?

10. How to integrate Spring Boot and ActiveMQ?

How to use Spring Boot to implement paging and sorting?

12, What is Swagger? Did you implement it with Spring Boot?

13. What are Spring Profiles?

14. What is Spring Batch?

15. What is a FreeMarker template?

16. How to use Spring Boot to implement exception handling?

17. Which Starter Maven dependencies do you use?

What is a CSRF attack?

What are WebSockets?

What is AOP?

What is Apache Kafka?

22. How do we monitor all Spring Boot microservices?

4.Spring Cloud

1. What is Spring Cloud?

2. What are the advantages of using Spring Cloud?

3. What does service registration and discovery mean? How is Spring Cloud implemented?

4. What is the significance of load balancing?

5. What is Hystrix? How does it achieve fault tolerance?

6. What is Hystrix circuit breaker? Do we need it?

7. What is Netflix Feign? What are its advantages?

8. What is Spring Cloud Bus? Do we need it?

5. The JVM interview questions

1, THE JVM three performance tuning parameters, JVM several important parameters

2. JVM tuning

3, JVM memory management, JVM common garbage collector, G1 garbage collector. GC tuning, Minor GC, Full GC trigger conditions

4. Java memory model

Java garbage collection mechanism

How does the JVM determine if an object is recyclable, and which objects can be used as GC root

7. OOM? How to check? What causes OOM? When does OOM appear

What is Full GC? GC? major GC? stop the world

Describe a full GC process in the JVM.

Class loading mechanism in JVM, class loading process, what is parent delegate model? Class loaders

11. How to determine whether there is a memory leak? What are some ways to locate the cause of Full GC?

12. What reference types are available in Java?

6.Java concurrent programming

1. What is the difference between daemon threads and local threads in Java?

What is the difference between a thread and a process?

3. What is context switching in multithreading?

4. The difference between deadlock and live lock, deadlock and starvation?

5. What is the thread scheduling algorithm used in Java?

6. What are thread groups and why are they not recommended in Java?

7. Why use Executor Framework?

The difference between Exector and Executors in Java?

How to find which thread is using the most CPU time on Windows and Linux?

10. What is atomic operation? What atomic classes are available in the Java Concurrency API?

What is the Java Concurrency API’s Lock interface? What are the advantages over synchronization?

12. What is Executors Framework?

What is a blocking queue? What is the implementation principle of blocking queues? How to implement the producer-consumer model using blocking queues?

14. What are Callable and Future?

15. What is FutureTask? Start tasks using the ExecutorService.

What is the implementation of concurrent containers?

17, There are several ways to implement multithreaded synchronization and mutex. What are they?

What are the conditions of competition? How do you find and solve competition?

How will you use Thread dump? How would you analyze Thread dump? 165

20. Why do we call run() when we call start()? Why can’t we call run() directly?

21. How do you wake up a blocked thread in Java?

22. What is the difference between CycliBarriar and CountdownLatch in Java?

23. What are immutable objects and how does it help write concurrent applications?

24, What is context switching in multithreading?

25. What is the thread scheduling algorithm used in Java?

26. What are thread groups and why are they not recommended in Java?

27. Why is using the Executor framework better than using applications to create and manage threads?

28. How many ways can you implement a thread in Java?

29. How do I stop a running thread?

What is the difference between notify() and notifyAll()?

31. What are Daemon threads? What does it mean?

Java how to achieve communication and collaboration between multiple threads?

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