java synchronized method

The volatile and synchronized usages in Java multithreading are analyzed in this paper. Share to everyone for your reference. The implementation methods are as follows: Copy Code code as follows: Package Com.chzhao; public class Volatiletest extends Thread { private static int count = 0; public void Run () {count++;} public static void Main (string[] args) {Thread threads[] = new thread

Turn from: Original: http://blog.csdn.net/luoweifu/article/details/46613015Author: LuoweifuSynchronized is a key word in Java and is a synchronous lock. It modifies objects in the following ways:1. Modify a code block, the modified code block is called the synchronous statement block, its scope is the curly braces {} In the code, the object is to call the object of this block of code;2. Modify a method, the

Synchronized keywords are the following 3 ways to apply the mainA modified instance method, which is used to lock the current instance, to obtain the lock of the current instance before entering the synchronization code; Instance lock, one instance lockModify the static method, for the current class object lock, before entering the synchronization code to obtain

In Java concurrent programming, use ReentrantLock to replace the synchronized keyword primitive.Tags: the Concurrent library package introduced by Java 5 provides ReentrantLock that can be reloaded into the synchronization lock to replace the synchronized keyword primitive, and provides better performance and more powe

= 0, then there is an operation a++, this variable a has visibility, but a++ is still a non-atomic operation, that is, the operation also has a thread safety problem.Volatile, synchronized, and final implementation visibility in Java.Atomic nature:　　atoms are the smallest units in the world and are indivisible. such as a=0; (a non-long and double type) This operation is indivisible, then we say this operation is atomic operation. Another example: a++

In two different situations 1): Non-Synchronized method to enter this object Answer: You can 2): The synchronization method to enter this object Answer: No, you can't. The first case of the original code /** * * * /package thread; /** * @author Administrator */public class TestClass { /** * * @param args * * public static void Main (string[] args) {

First, Java Concurrency FoundationWhen an object or variable can be shared by multiple threads, it is possible to cause problems with the logic of the program. There is a variable in an object i=0, there are two threads, a, a, I plus 1, this time there is a problem to appear, the key is that I plus 1 of the process is not atomic operation. To increment the I, the first step is to get the value of I, when a gets the value of I is 0, before a new value

lock and response interrupt lock, which gives us a lot of flexibility. For example: If a, B2 thread to compete lock, a thread get lock, b thread wait, but a thread this time really have too many things to deal with, is not return, B thread may be able to wait, want to interrupt themselves, no longer wait for this lock, to deal with other things. This time Reentrantlock provides 2 mechanisms, first, the B thread interrupts itself (or another thread interrupts it), but Reentrantlock does not resp

Data synchronization need to rely on the lock, the synchronization of the lock who depends on? The answer given by synchronized is that it relies on the JVM at the software level, and lock gives the option to rely on special CPU instructions at the hardware level, and you may further ask: How does the JVM's bottom layer implement synchronized?The JVM referred to in this article refers to the 6u23 version of

Condition: The condition interface describes the condition variables that may be related to locks. These usages are similar to using object.wait to access an implicit monitor, but provide more powerful functionality. It should be noted that a single lock may be associated with multiple condition objects. To avoid compatibility issues, the name of the condition method differs from the corresponding OBJEC version. In the condition object, t

1. When synchronized is used as a function modifier Public synchronized void methodaaa () {} Public void methodaaa () {{} 2. Synchronization block, for exampleCodeAs follows:Public void method3 (someobject so){Synchronized (SO){//.....}}When a specific object is used as a lock, you can write it like this.ProgramBut when there is no clear object as the lock, just

(); Start preheating for (int i = 0; i Although StringBuffer's append is a synchronous method, the StringBuffer in this program belongs to a local variable and does not escape from the method, so the process is thread-safe and can be eliminated. Here are the results of my local execution: In order to minimize the impact of other factors, the bias Lock (-xx:-usebiasedlocking) is disabled he

Copyright NOTICE: This article for Bo Master original article, without Bo Master permission not reproduced. http://blog.csdn.net/chenchaofuck1/article/details/51045134Java when writing multi-thread program, in order to ensure thread security, need to synchronize data, often use two kinds of synchronization is synchronized and re-enter lock Reentrantlock.Similar points:There are many similarities between these two modes of synchronization, which are bo

This time, we're not using a well-known inner class. The program controls data and executes programs independently.5 threads rotate the thread pool synchronized wait notify by a given ruleThe code is as follows:1. Independent internal Control data classPackage com.lovo.homework02;/** * Class: Separate internal data to make it easy to modify and control * @author Abe * */public class Printthreadcontext {/** * allowed to execute the key of the thread T

listener thread, you have to prove one thing to believe me, that is, the main thread of the game and the key listener thread is not the same thread, but it can be a set of related threads (this is very simple, as long as there is the same object lock can be).You can try it, in Java, the key is a dedicated thread, usually a background thread like awt-eventqueue-0, and the code you write is running in another thread.So, actually when your game is pause

the student class we overwrite the CompareTo and equals methods, but our CompareTo and equals are based on different, one is age and one is based on name. The results obtained by comparison are likely to be different. So knowing the reason, we are good to modify: the comparison between the two to maintain consistency.For the CompareTo and equals two methods we can conclude that: CompareTo is to determine whether the position of the elements in the sorting is equal, equals is to determine whethe

The difference between synchronized and lockSynchronizeThe lock object can be any object, because the monitor method must have a lock object so that any object can be called by a method so that it is extracted into the object class to define the Monitor methodSo that the lock object and the monitor object are the same, as long as the lock object is created it is