Shulou(Shulou.com)06/02 Report--

This article mainly explains "what is the learning method of Java concurrent programming". The content of the article is simple and clear, and it is easy to learn and understand. Please follow the editor's train of thought to study and learn "what is the learning method of Java concurrent programming".

First: the basis of concurrency and multithreading first need to learn the basic knowledge of concurrency, what is concurrency, why concurrency, the concept of multithreading, the concept of thread safety and so on. Then learn to use Thread or other thread implementation methods in Java to understand thread state transitions, thread methods, thread communication methods, and so on. Second: JMM memory model any language is ultimately run on the processor, JVM virtual machine in order to give developers a consistent programming memory model, need to develop a set of rules, this set of rules can be implemented on different machines of different architectures, and provide programmers with a unified JMM memory model. Therefore, understanding the JMM memory model is also a key point to understand the principle of Java concurrency, in which it is particularly important to understand instruction rearrangement, memory barrier, and visibility principles. JMM only guarantees happens-before and as-if-serial rules, so atomicity, visibility and ordering may arise in multithreading concurrency. The following will describe how Java solves these three major problems. Third: keywords such as synchronized,volatile,final for the three major problems of concurrency, volatile can ensure atomicity and visibility, and the three characteristics of synchronized can be guaranteed (allow instruction rearrangement). Synchronized is implemented based on the operating system's mutex lock instructions, while volatile and final implement its memory semantics according to JMM. You also need to learn about the CAS operation here, which not only provides volatile-like memory semantics, but also guarantees the atomicity of the operation because it is implemented by hardware. The bottom layer of Lock in JUC is implemented using volatile plus CAS. Synchronized will also try to optimize heavy-level locks with cas operations. It is necessary to understand these keywords. Four: JUC package after understanding the above content, you can take a look at the content of JUC. JUC provides including Lock, atomic manipulation classes, thread pools, synchronization containers, utility classes and so on. These classes are all based on AQS, so it's important to understand how AQS works. In addition, you can also take a look at the common scenarios of Fork/Join and JUC, such as producers and consumers, blocking queues, and read-write containers.

Fifth: the practice of these contents, in addition to the JMM part of the content is relatively difficult to implement, such as the basic use of multithreading, the use of JUC can better understand its principle in code practice. It is necessary to try some more scenarios, or to find some classic concurrency scenarios on the Internet, or to refer to the examples of others to deepen our understanding in practice. Six: supplement because many Java novices may have no concept of concurrent programming, put a good summary here, briefly mention several more important points in concurrent programming, is also a more basic point, is it a good start, after a general understanding of these basic contents, can we better carry out the study of the following details. Thank you for your reading, the above is the content of "what is the learning method of Java concurrent programming". After the study of this article, I believe you have a deeper understanding of what the learning method of Java concurrent programming is, and the specific use needs to be verified in practice. Here is, the editor will push for you more related knowledge points of the article, welcome to follow!

Welcome to subscribe "Shulou Technology Information " to get latest news, interesting things and hot topics in the IT industry, and controls the hottest and latest Internet news, technology news and IT industry trends.