multithreading vs concurrency in java

[Java concurrent programming] 9: deadlock (including code), java concurrency A deadlock may occur when the thread needs to hold multiple locks at the same time. Consider the following situations: Thread A currently holds the lock1 lock and thread B currently holds the lock2 lock. Next, when thread A still holds lock1, it tries to get lock2 because thread B is hol

);V.stopit ();Thread.Sleep (2000);SYSTEM.OUT.PRINTLN ("Finish main");System.out.println (V.getstop ());}Iv. Rules of Happen-beforeProcedural Order Principle: the serialization of semantics within a threadVolatile rules: The write of volatile variables, which occurs first in the read, which guarantees the visibility of volatile variablesLock rule: Unlocking (unlock) must occur before the subsequent locking (lock)Transitivity: A precedes b,b before C, then a must precede CThe start () method of th

I. BACKGROUNDCache is our development in order to improve the performance of the system, the data of the frequent access to the business first put the processing results in the cache, the second time without the same business data in the re-processing, which improves the performance of the system. There are several types of caches:(1) Local cache.(2) Database cache.(3) Distributed cache.Distributed cache is commonly used memcached ,memcached is a high-performance distributed memory cache server,

values or change their values inside the thread. Threadlocal instances are typically the private static property that you want them to associate with the thread state.Second: Java Concurrency interview questions1: What is the executors framework?The Executor framework is introduced in Java 5 with the Java.util.concurrent.Executor interface. The executor framewor

Original address: Https://www.jianshu.com/p/f3f6b12330c1 understanding and resolving Java Concurrency modification exceptions concurrentmodificationexceptionI do not know if the reader in the Java development process encountered similar exception information Exception in thread "main" java.util.ConcurrentModificationException, The following is a brief description

Java concurrency series [6] ---- Semaphore source code analysis, java ---- semaphore Semaphore is a common class in the JUC package. It is an application in the AQS sharing mode and allows multiple threads to operate on shared resources at the same time, in addition, it can effectively control the number of concurrent jobs and use it to control traffic. Semaphore

) {e.printstacktrace (); } System.out.println ("Test ends ..."); } } } classMyThreadextendsThread { Public voidrun () {Sync sync=NewSync (); Sync.test (); } } Public classMain { Public Static voidMain (string[] args) { for(inti = 0; I ) {thread thread=NewMyThread (); Thread.Start (); } } } Operation Result:Test start:Test end:Test start:Test end:Test start:Test end:The above code uses synchronized (Sync.class) to achieve the effect of global locking.Finally, th

and concurrency issues are among the questions that interviewers prefer to ask in a Java technology interview. Here, the most important questions are listed from the interview point of view, but you should still have a solid grasp of the basics of Java multithreading to match the problems you encounter later.1. Java Mu

() {Clear Business Full.notifyall ();}Think of more targeted object-oriented programming. Similar issues with databases: Dirty reads: The first thing reads the data that the second thing is updating, and if the UPDATE statement is not yet complete, the first thing reads only the data in a process, not the actual result. Oracle's Things by default: Read Committed (commit read), the problem does not occurExclusive Lock: Gets an exclusive lock when the data is changed.Shared Lock: The query acqui

In the [high Concurrency Java II] Multithreaded Foundation, we have initially mentioned basic thread synchronization operations. This time, we will mention the synchronization control tool in the contract. 1. Use of various synchronization control tools 1.1 Reentrantlock Reentrantlock sense is synchronized's enhanced version, synchronized is characterized by the use of simple, all to the JVM to deal with