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1. Classification of Java locks (reference link: https://tech.meituan.com/2018/11/15/java-lock.html ) (1) Optimistic lock VS pessimistic lock: * * optimistic Lock: * * Lock the data first to ensure that the data will not be modified by other threads. The synchronized keyword and the implementation class of Lock are pessimistic locks. It is su ...

JUC is a part of my job that I don't use very much, but I often get asked about it in a helpless interview, so I'll learn about JUC today. JUC is all called Java. Util. The concurrent package is a toolkit for Java, so why is JUC a frequent question for interviews? Because JUC includes multithreading, atomicity, locks and other heavy content, i ...

Chapter 3 - management of shared model (4) Thread state Re understand thread state transition (key) Suppose there is a thread Thread t Case 1 new -- > runnable When the t.start() method is called, new -- > runable Case 2 runnable < – > waiting After the t thread obtains the object lock with synchronized(obj)C ...

concept The full name of CAS is Compare And Swap, which means compare and exchange. It is the atomic operation of CPUCAS is an abstract idea, not a concrete implementationCAS operation has three parameters: memory address of the value to be modified, expected value and new valueThe main idea is to judge whether the value of a location in memor ...

1. Overview of thread waiting wake-up mechanism2. The wait and notify methods in the object class implement thread waiting and wake-up3. The await post signal method in the condition interface realizes thread waiting and wake-up4. Restrictions on the use of object and Condition5. Introduction to locksupport class6. park wait and unpark wake-up ...

1, AtomicInteger/** * @author Java And algorithm learning: Monday */ public class AtomicInteger { //No volatile public AtomicInteger count = new AtomicInteger(0); //No synchronized public void m() { for (int i = 0; i < 1000; i++) { //count++ count.incrementAndGet(); } } pub ...

Locks are used to control how multiple threads access shared resources. Generally speaking, a Lock can prevent multiple threads from accessing shared resources at the same time (but some locks can allow multiple threads to access shared resources concurrently, such as read-write locks). Before the emergence of the Lock interface, Java progra ...

Lock Lock is the core tool in J.U.C. its function is the same as synchronized explained earlier. It is also used to solve thread safety problems in multithreaded environment. In the J.U.C package, the lock mechanism is used in many places. J. The full name of U.C is java.util.concurrent. It is a common toolkit in concurrent programming. Th ...