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1, Semaphore Semaphore definition Semaphore literally means semaphore. Its function is to control the number of threads accessing specific resources. The bottom layer depends on the State of AQS. It is a tool class commonly used in production. Common methods of Semaphore Construction method public Semaphore(int permits) public Semaphore(in ...

Chapter 3 - management of shared model (3) wait-notify Little story - why wait Because the conditions are not met, Xiaonan cannot continue the calculationBut if Xiaonan keeps occupying the lock, others will have to block all the time. The efficiency is too low So Lao Wang opened a single Lounge (calling the wait method) and asked Xiao Nan ...

ThreadLocal uses: 1.set: set the private variable to the thread 2.get: get ThreadLocal from thread 3.remove: remove ThreadLocal from the thread. 4.initialValue: initialization 5.withInitialValue: initialization (lambda expression) Usage scenario: 1. Solve thread safety problems 2. Realize thread level data transmission Disadvantages: 1. Data ...

1, Four ways to initialize threads Inherit Thread classImplement Runnable interfaceImplement Callable interface + FutureTask (you can get the returned results and handle exceptions)Thread pool Inherit the Thread class and implement the Runnable interface: the main process cannot obtain the operation result of the Thread.Implementation o ...

Java thread summary (I) 1. Thread life cycle 1) Create (3 ways) a. Inherit Thread class public class ThreadDemo1 extends Thread{ @Override public void run() { for(int i=0;i<10;i++) { System.out.println(i); } } } b. Implement Runnable interface public class ThreadDemo2 implements Runnable { @Override public void ru ...

Chapter 3 - management of shared model (1) Contents of this chapter Sharing problemsynchronizedThread safety analysisMonitorwait/notifyThread state transitionActivityLock Problems caused by sharing Little story Lao Wang (operating system) has a powerful abacus (CPU). Now he wants to rent it and earn some extra money Xiao Nan and Xia ...

abnormal Concepts and Systems of Exceptions Classification of Exceptions public static void main(String[] args) throws ParseException { SimpleDateFormat simpleDateFormat = new SimpleDateFormat("yyyy-MM-dd"); Date date = simpleDateFormat.parse("202106-01"); //ParseException System.out.println(date); } public static void main ...

Python crawler, data analysis, website development and other case tutorial videos can be viewed online for free https://space.bilibili.com/523606542 Python learning exchange group: 1039649593 Use of threading module python's thread module is the underlying module, and python's threading module wraps thread, which can be used more conve ...

Redis Chapter 4 implementation of distribution lock and Lua script + native code implementation In the previous article, redistribute was introduced. The application of redistributed in distributed locks is very simple and convenient, but redistribute itself is a encapsulated framework. In this section, we explore the implementation of Redis's ...

@Yixian loves potatoes 1. Process Each process has its own independent memory space and system resources(running program) cpu time slice: refers to system resources and memory space 2. Thread It is an execution line in the process Each thread performs a taskThread is the basic scheduling unit of CPU 3. Relationship between process and thr ...