Preface
The development of hardware has been extremely rapid. In the context of multi-core CPUs, the trend of concurrent programming has been spawned. Through concurrent programming, the computing power of multi-core CPUs can be maximized and performance improved . Concurrent programming is a technology that allows multiple tasks executed in series to run concurrently. This technology can significantly improve the throughput of applications, shorten the response time of requests, and allow programs to work together. Writing high-quality concurrent code is extremely difficult. It has extremely high requirements for the program. It not only needs to understand the most basic operating principles, but also requires programmers with clear thinking and meticulous logic. Almost all Internet companies must ask questions during interviews. The market urgently needs talents who truly master concurrent programming.
But this technology always feels unpredictable to the newcomers, and because of the unknown, no good learning materials can be found. In line with the principle that good things are to be shared , so the Internet Lei Feng (Editor I) collected a complete set of materials for everyone to learn, suitable for Java multi-threaded developers, Java concurrent developers, system architecture Teachers, big data developers, and other people interested in multi-threading technology. Friends in need can help comment + forward, follow me private message [111] to get it for free! Everyone, look down~
These documents cover processes, threads, concurrency, parallelism and Java concurrency tools, concurrency problems and solutions on the Java platform, as well as concurrency in other areas.
Concurrent programming
- Process and thread
- Java thread
- Shared model
Principles
Mode articles
Application
effectiveness
- Use multithreading to make full use of CPU
limit
- Limit the use of CPU
- Limit the use of shared resources
- Current limit per unit time
Mutually exclusive
- Pessimistic mutual exclusion
- Optimistic value
Synchronous and asynchronous
- Need to wait for the result
- No need to wait for results
Cache
- Cache update strategy
- Read-write locks for consistent caching
Divide and conquer
- Case-word count
- Case-Sum
Overall planning
- Case-Boiling water to make tea
timing
- Regular execution
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Java multithreaded concurrent programming
Catalog overview
Since the length of the article is already very long here, this document is only for you to show the catalog
Chapter 1 explains the basics of Java multithreading, including the use of the core API of the Thread class.
Chapter 2 explains the control of concurrent access in multiple threads
Chapter 3 introduces the communication and interaction between threads.
Chapter 4 explains the synchronized keyword, which is more troublesome to use, so the Lock object is provided in Java 5 to better realize the synchronization processing during concurrent access, including related technical points such as read-write locks.
Chapter 5 explains the Timer class, its internal implementation is the use of multithreading technology. The scheduled task execution of the timer is a very important technical point, including in-depth use during Android development, so it will be explained in detail for readers. The singleton pattern explained in Chapter 6. Chapter 7, Checking For Leaks
Thread learning is not as simple as JDBC-, with a steep learning curve, many detours and "pits". To learn these hotspot technologies, Java multithreading technology is inevitable. I believe this document can lead you to win the "technical highland".
At the end of the article, let’s take a look at these 19 real interview questions from major manufacturers of concurrent programming for everyone to check and fill in the gaps. How many can you answer? If you don’t, it’s okay. I also prepared a PDF of interview topics with answers for everyone.
- Question 1: What is thread safety?
- Question 2: What is the visibility issue of shared variables?
- Question 3: Atomicity?
- Question 4: Introduction to CAS?
- Question 5: What is a reentrant lock?
- Question 6: Synchronized keyword?
- Question 7: Introduction to ReentrantReadWriteLock?
- Question eight: volatile variables?
- Question 9: Optimistic lock and pessimistic lock?
- Question ten: Exclusive lock and shared lock?
- Question ten -: fair lock and unfair lock?
- Question 12: Introduction to AbstractQueuedSynchronizer?
- Question 13: How does CountDownLatch work?
- Question 14: ReentrantLock exclusive lock principle?
- Question 15: ReentrantReadWriteLock principle?
- Question 16: What is the reordering problem?
- Question 17: What is an interrupt?
- Question 18: How does FutureTask work?
- Question 19: A brief description of the principle of ConcurrentHashMap?
Write at the end
In recent years, concurrent programming has gradually become a necessary skill. The beginning of the article also said that it is mainly hardware drivers and the rapid development of the domestic Internet industry. Traditional middleware and databases can no longer protect us from wind and rain, but Became the bottleneck. I have to say that if you learn this thing well, you can get a salary increase (dog head). At present, there are many kinds of information on the market, and there is very little system of information. If a friend is interested in this set of information shown above, he only needs to comment + like, follow me and send a private message [111] to take away all, hope Everyone can make progress together, raise the salary, don't stop learning, let your life not leave regrets!
