mastering concurrency programming with java 8

different I/O. A common way is InputStream's read () method, which blocks until a byte of data is read from the stream, it can block indefinitely, and therefore cannot specify a time-out;4, a thread can also block waiting for exclusive access to an object lock (that is, to wait for a lock that the synchronized statement must have blocked).Note that not all blocking states are interruptible, the first two of the above blocking states can be interrupted, and the latter two will not respond to int

separately./*** Implement Condition Interface*/ Public classConditionobjectImplementsCondition, java.io.Serializable {Private Static Final LongSerialversionuid = 1173984872572414699L; /*** The first node of a conditional queue. */ Private transientAbstractqueuedsynchronizer.node Firstwaiter; /*** The last node of the conditional queue. */ Private transientabstractqueuedsynchronizer.node Lastwaiter;}From which you can see it or implement the condition interface, and what specification does

: DinnerIn the code, we define a re-entry lock object as a common lock for two threads, and call the Lock.newcondition () method to get a condition object for multi-threaded collaboration, and the condition await () method is equivalent to the wait of object () method, the signal () method is equivalent to the Notify () method of object, and condition also has a signalall () method equivalent to the Notifyall () method of object. One thing to note is that you should not misuse the wait () method

different I/O. A common way is InputStream's read () method, which blocks until a byte of data is read from the stream, it can block indefinitely, and therefore cannot specify a time-out;4, a thread can also block waiting for exclusive access to an object lock (that is, to wait for a lock that the synchronized statement must have blocked).Note that not all blocking states are interruptible, the first two of the above blocking states can be interrupted, and the latter two will not respond to int

with final retouching, it is not always possible to have an object that is immutable, because a reference to a Mutable object can be saved in a field of final type. When the condition is met, the object is immutable: 1. Objects cannot be modified once they are created 2. All fields of the object are final type 3. Object is created correctly (this does not escape at the time of creation) An immutable object is only external and can not change its state and is internally maintainable. Build imm

Blocking queue Blocking queue is the content of Java 5 concurrency new features, and the interface for blocking queues is java. util. concurrent. blockingQueue, which has multiple implementation classes: ArrayBlockingQueue, DelayQueue, LinkedBlockingQueue, PriorityBlockingQueue, and SynchronousQueue. The usage is similar. For details, refer to the JDK documentati

Java high concurrency has three pieces of knowledge: Synchronizer: Synchronizer, how to communicate with each other, synchronization, etc. synchronization container: JDK provides a synchronous container, such as Concurrentmap,concurrentlist, Blockqueen, ThreadPool: Thread pool, Executor,java the thread pool provided on top two, a lot of practical problems can be

follows: Copy Code code as follows: FileSearch FileSearch = new FileSearch ("c:\\", "Autoexec.bat"); Thread thread = new Thread (FileSearch); Thread.Start (); 8. Wait 10 seconds, then disconnect the thread. The code is as follows: Copy Code code as follows: try { TimeUnit.SECONDS.sleep (10); catch (Interruptedexception e) { E.printstacktrace (); } Thread.Interrupt (); 9. Follow the exam

thread b Call the threadb.interrupt () method to be able to wait in thread B . Note that when a thread acquires a lock, it is not interrupted by the interrupt () method. Therefore, when a lock is acquired through the lockinterruptibly () method, it can be interrupted if it cannot be obtained and only waits. And with synchronized modification, when a thread waits for a lock, it cannot be interrupted, only waiting. ReentrantlockUsing the lock interface directly, we need to implement a lot of meth

servlet needs to save information when it processes the request.3. Atomic NatureExample 2: A non-thread-safe servlet Public class Implements Servlet { privatelong count = 0; Public Long GetCount () { return count; } Public void Service (ServletRequest req, Servletresponse resp) { = extractfromrequest (req); = factor (i); }}Cause of Thread insecurity: count++ is not an atomic operation, it contains three steps: Read-write-Modify. If two threads read a va

also some optimizations such as the following:Public String getstoogenames () {listIn this code above, at least the Stooges lock gets Freed 4 times (the last ToString () is also one time, and an intelligent runtime compiler parses these calls, thus merging the acquisition of locks into one lock acquisition and release. and recompile the getstoogenames to return only the results of the first execution after the first execution.The cost of non-competitive synchronization is already very small, so

the lock for each I, which is the acquisition of all the segment locks of the entire container . synchronized(Locks[i%N_locks]) {Buckets[i]=NULL; } } }}3. Avoid hotspot domainsHotspot Resource lock competition is intense, resulting in performance issues4. Override exclusive Locksuch as: Read-write Lock: Read read can be parallel, to prevent exclusive; use atomic State amount; Use concurrent container; Use immutable objects, etc.5. Reduce context SwitchingTasks are toggled i

"); Socket socket=new socket (addr,5203); BufferedReader in=new BufferedReader (New InputStreamReader (Socket.getinputstream ())); PrintWriter out=new PrintWriter (Socket.getoutputstream ()); for (int i =0; iCustomer B-side code:Import Java.io.*;import java.net.*;p ublic class Talkclient {public static void main (string args[]) {string ROOTPATH=TALKC Lient.class.getResource ("/"). GetFile (). toString (); String fileName =rootpath+ "Initialize.txt"; String file = "My name is yi! Nice to mee

();while (!executor.isterminated ()) {System.out.printf ("Pool size:%d,active count:%d,completed task:%d\n", Executor.getpoolsize (), Executor.getactivecount (), Executor.getcompletedtaskcount ()); }}} class task implements runnable{ public void Run () {System.out.println (thread.currentthread (). GetName () + "is called"); try {thread.sleep (100);} catch (Interruptedexception e) { //TODO auto-generated catch block E.printstacktrace (); }}} Results:Pool-1-thread-2 is calledPool-1-thread-4 is c

Runnable object to execute at some point in the future. Functionally similar to timers, which are used very frequently in web systems.SemaphoreA normal lock (from a concurrent.locks or built-in synchronized lock) allows only one task to access a resource at any given time, while a count semaphore allows n tasks to access the resource at the same time. In fact, the semaphore is less used: 1. Resource access is mostly only 1 to 2 of the difference, there is no 2 to many differences, thread-safe o

The above has summed up the past life of Aqs, with this foundation we can further learn the concurrency tool class. The first thing we want to learn is Reentrantlock, this article will be from the background of Reentrantlock, source code principle and application to learn reentrantlock this concurrency tool class. 1. Create a background We have already learned synchronized, the key word to ensure that the o

Introduction to the first chapter Pick a book Threads share process-wide resources such as memory handles and file handles, but each thread has its own program counter (Programs Counter), stacks, and local variables. Multiple threads in the same program can also be scheduled to run on multiple CPUs at the same time. Chapter II Thread Safety Pick a book The primary synchronization mechanism in Java is the keyword synchronized, which prov

randomness into the retry mechanismThe 11th chapter performance and can extend the straight-temperedPerformance metrics: Speed of operation, processing powerHow to evaluate? How to weigh?Amdahl LawCost of thread Ingestion: Context switch, memory synchronization,Modern JVMs can automatically optimize lock and memory reorderingReduce lock contention: Reduce lock hold time, reduce lock request frequency, use exclusive lock with protocol mechanism1. Fast-in fast-out2. Decomposition of multiple vari

1.1.Get execution ResultsUse the callable interface provides easy access to task execution results. Executorservice executorservice = Executors.newfixedthreadpool (2 new callable () {@Override public Integer call () throws Exception { return 1;} }); try { int ret = Future.get (); System.out.println ( "return:" + ret);} catch (interruptedexception e) {e.printstacktrace ();} catch (executionexception e) {e.printstacktrace ();} after the successful execution of the task is com

();Handler3 h3 = new Handler3 ();Handler4 h4 = new Handler4 ();Handler5 h5 = new Handler5 ();Disruptor.handleeventswith (H1, H2);Disruptor.after (H1). Handleeventswith (H4);Disruptor.after (H2). Handleeventswith (h5); Disruptor.after (H4, H5). Handleeventswith (H3);To believe that you have some knowledge of disruptor, so many producers of multiple consumers how to achieve, in fact, and the above code very similar, nothing more than the producers are holding Ringbuffer can publish just.This arti