Today, the first-line architect of a major factory will tear down the microservice architecture and take you to the battle against multithreading, JVM, Redis and MySQL. If you don't believe this, you won't understand it after reading it!
Note: The documents of all the following interview questions (including answers), as well as the compilation of notes and the actual pdf, can be shared with everyone for free
Multithreading (English: multithreading) refers to a technology that implements concurrent execution of multiple threads from software or hardware. A computer with multi-threading capability can execute more than one thread at the same time due to hardware support, thereby improving overall processing performance. In a program, these independently running program fragments are called "threads", and the concept of programming with them is called "multithreading". A computer with multi-threading capability can execute more than one thread at the same time due to hardware support, thereby improving overall processing performance.
One, multi-thread related
(1) Multi-threaded interview topics
- What is the use of multithreading?
- What is the difference between thread and process?
- How many ways does Java implement threads?
- What is the difference between start() and run()?
- How to terminate a thread? How to terminate the thread gracefully?
- What are the several states of the life cycle of a thread? How do they flow between them?
- What is the difference between wait() and sleep() methods in threads?
- What are the methods for multi-thread synchronization?
- What is a deadlock? How to avoid deadlock?
- How to communicate between multiple threads?
- How does the thread get the returned result?
- What does the violatile keyword do?
- How to ensure that the three threads T1, T2 and T3 are created in order?
- How to control only 3 threads running at the same time?
- Why use thread pool?
- Several commonly used thread pools and talk about their working principles.
- What is the difference between the submit() and execute() methods of thread pool startup threads?
- What is the difference between CyclicBarrier and CountDownLatch?
- What is livelock, starvation, no lock, deadlock?
- What is atomicity, visibility, and order?
Answers to multi-threaded interview topics:
(2) Java multi-threaded combat technology-notes
- Java multithreading skills
- Concurrent access to objects and variables
- Inter-thread communication
- Use of Lock
- Timer
- Singleton mode and multithreading
- Supplements
Two, JVM related
(1) JVM performance tuning interview topics:
- JVM memory area division
- JVM execution subsystem
- Garbage collector and memory allocation strategy
- Write efficient and elegant Java programs
- Performance optimization
JVM is the abbreviation of Java Virtual Machine (Java Virtual Machine). JVM is a specification for computing devices. It is a fictitious computer that is realized by simulating various computer functions on an actual computer.
(2) Explain the JVM-core combat
- Approaching Java
- Java memory area and memory overflow exception
- Garbage collector and memory allocation strategy
- Virtual machine performance monitoring and troubleshooting tools
- Tuning case analysis and actual combat
- Class file structure
- Virtual machine class loading mechanism
- Virtual machine bytecode execution engine
- The case and actual combat of class loading and execution subsystem
- Early (compile time) optimization
- Late (runtime) optimization
- Java memory model and threads
- Thread safety and lock optimization
Three, MySQL related
(1) MySQL interview topics:
- What are the technical characteristics of Mysql?
- What is the difference or pros and cons between Hash index and B+ tree?
- What is the default port of Mysql server?
- Please briefly describe the names of the four transaction isolation levels supported by InnoDB in Mysql and the differences between each level?
- What is the usage of ENUM in Mysql?
- What is ACID? Can you elaborate on it?
- What storage engine is used in Mysql?
- What is the Mysql driver?
- What are the method commands for MYSQL database server performance analysis?
- What isolation level does Innodb use?
- How do we run batch mode in mysql?
- How many TRIGGERS are allowed in Mysql table?
- What field type is good for recording currency in mysql
- Under what circumstances are MYSQL data tables easily damaged?
- What kind of locks does MySQL have? Isn't it a bit hindering concurrency efficiency to lock like the above?
MySQL has become the most popular open source database in the past due to its high performance, low cost, and good reliability. Therefore, it is widely used in small and medium-sized websites on the Internet. As MySQL continues to mature, it is gradually being used in more large-scale websites and applications. The "M" in the very popular open source software portfolio LAMP refers to MySQL.
(2) MySQL (from entry to actual combat) notes
- MySQL architecture and history
- MySQL benchmark
- Server performance analysis
- Schema and data type optimization
- Create high-performance indexes
- Query performance optimization
- MySQL advanced features
- Optimize server settings
- Operating system and hardware optimization
- copy
- Scalable MySQL
- High availability
- MySQL in the cloud
- Application layer optimization
- Backup and restore
- MySQL user tools
Four, Redis related:
(1) Redis interview topic
- What is Redis? Briefly describe its advantages and disadvantages?
- What are the advantages of Redis over memcached?
- Which data types does Redis support?
- What kinds of data elimination strategies does Redis have?
- What is the maximum capacity that a string value can store?
- Why does Redis need to put all data in memory?
- Under what circumstances will the Redis cluster solution cause the entire cluster to be unavailable?
- There are 2000w data in MySQL and only 20w data in redis. How to ensure that the data in redis are all hot data?
- What are the advantages and disadvantages of Jedis and Redisson?
- What is the master-slave replication model of Redis cluster?
- How to set the expiration time and permanent validity of Redis key?
- What is cache penetration? How to avoid it? What is a cache avalanche? How to avoid it?
- Have you ever used Redis distributed lock and how is it implemented?
- Have you used Redis as an asynchronous queue? How do you use it? What are the disadvantages?
Redis is a key-value storage system. Similar to Memcached, it supports relatively more value types for storage, including string (string), list (linked list), set (collection), zset (sorted set - ordered set) and hash (hash type). These data types all support push/pop, add/remove, intersection, union and difference, and richer operations, and these operations are all atomic. On this basis, Redis supports a variety of different sorts. Like memcached, in order to ensure efficiency, data is cached in memory. The difference is that redis periodically writes updated data to disk or writes modification operations to additional record files, and on this basis, it realizes master-slave (master-slave) synchronization.
(2) Explain Redis in a simple way
- Getting started
- Getting to know Redis
- Use Redis to build web applications
- Core Concepts of Part Two
- Redis commands
- Data security and performance guarantee
- Use Redis to build support programs
- Use Redis to build application components
- Search-based applications
- Build a simple social network
- The third part of advanced content
- Reduce memory usage
- Extend Redis
- Redis Lua script programming
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