mastering concurrency programming with java 8

Java Socket multi-thread programming, processing millions of data concurrency. Thanks to the Code shared by the experts on the Internet, I assembled the code into the rest based on the needs of our project. The general framework is this mode. What needs to be modified is the transmission of business data, others do not need to be modified. In the spirit of learni

Public classReenterlockImplementsrunnable{ Public StaticReentrantlock lock=NewReentrantlock (); Public Static intI=0; @Override Public voidrun () { for(intj=0;j) {lock.lock (); Try{i++; }finally{lock.unlock (); } } } Public Static voidMain (string[] args)throwsinterruptedexception {reenterlock tl=NewReenterlock (); Thread T1=NewThread (TL); Thread T2=NewThread (TL); T1.start (); T2.start (); T1.join (); T2.join (); System.out.println (i); }}To reuse Lock:1 Public

Java concurrency programming Summary 4 -- ConcurrentHashMap improvement in jdk1.8, concurrenthashmap I. a brief review of the design of ConcurrentHashMap in jdk1.7 First, let's take a look at the design of the ConcurrentHashMap class in jdk1.7. Its basic structure is as follows: Each segment is a HashEntry Public class ConcurrentHashMap 2. Improvements in jdk

getqueuelength () { int n = 0; for (Node p = tail; P! = null; p = p.prev) { if (p.thread! = null) ++n; } return n;}Iterate from the end of the tail and accumulate N. Of course, this method and the method above may be inaccurate, because it is possible for the other threads to add node to the end of the queue when traversing.The rest of the methods are similar, you can go to see for yourself.Legacy issuesThe Reentrantlock process has been basically clear to the mana

Important Concepts Synchronous (synchronous) and asynchronous (asynchronous) Synchronous Wait method returns Asynchronously returns, continuing the next call Concurrency (Concurrency) and parallelism (Parallelism) Concurrency is consistent with parallel external performance Single-core CPUs cannot be parallelized, but can

==null?null:newMutablePoint(loc);}publicsynchronizedvoidsetLocation(Stringid,intx,inty){MutablePointloc=locations.get(id);if(loc==null)thrownewIllegalArgumentException("NosuchID:"+id);loc.x=x;loc.y=y;}privatestaticMapMapnew HashMapfor(Stringid:m.keySet())result.put(id,newMutablePoint(m.get(id)));returnCollections.unmodifiableMap(result);}} There is only one locations in the entire object, and we use the final adornment to guarantee its safe creation.But that's not enough, but we're not r

); } //Pause for 1 seconds. Try{thread.sleep (1000);} Catch(interruptedexception E) {e.printstacktrace ();} //Change the Conditions. Turn=next; //inform the next worker to start working. condition.signal ();}finally{//Release the Lock. Lock.unlock ();} } //the lock that is Used. PrivateLock lock =NewReentrantlock ();//the condition Variable. PrivateCondition Condition =lock.newcondition ();//the variable to be monitored by the condition. Private volatile intTurn = 0; } public Static voidmai

{ //in a stable state. Attempt to insert a new node if(CurTail.next.compareAndSet (NULL, NewNode)) { //Insert successful, try to push tail node, this step can be helped by another thread if it is not completedTail.compareandset (curtail, newNode); return true; } } } } } }}ABA IssuesIn some algorithms, if the value of V is first changed from a to B, then B becomes a.The

the key value pair for that index is not what we are looking for, the next index position is computed by the Nextindex method until the target key value pair is found or empty. Hash conflict: Elements at the same index position in HashMap are kept in the same index position in a linked list, whereas in Threadlocalmap, the data structure of the linked list is not used, but instead (the current index position + 1) The result of the length modulus as the location of the same index element: The N

the subtasks to thread to execute . Note that this method must use runnable as the parameter of the thread class, and then create a new thread to execute the subtask through the start () method of the thread. If you call Runnable's Run method, you will not create a new thread, which is no different from a normal method call.In fact, looking at the implementation source code of the thread class will find that the thread class implements the Runnable interface.In

the application. 4, the level of competition is not true Different levels of shared data and execution of local computing will show a different level of competition, with different performance and scalability 5, the elimination of useless code The compiler may delete code that is meaningless or does not produce results or predictable results Make the results as unpredictable as possible Iv. Other test methodsCode review (Manual Check Code), Race Analysis too

that the 65525 reading lock is not enough, you can rewrite the read-write lock yourself, for example, the first 24 bits of the assigned int state are read locks, and the last 8 bits are write locks.The read-write lock also provides new methods such as final int getreadholdcount (), which returns the number of read locks the current thread has acquired. Since the read state holds the sum of the number of read locks for all threads acquiring read locks

going to be used.　　8) Destroy methodThe Destroy method is also an obsolete method. Basic will not be used.Here are a few ways to relate to thread properties:1) getIdUsed to get the thread ID2) GetName and SetNameUsed to get or set the thread name.3) GetPriority and SetPriorityUsed to get and set thread priority.4) Setdaemon and IsdaemonUsed to set whether the thread is a daemon thread and whether the thread is a daemon thread.The difference between a

lock to make all the changes, using volatile for read-only operations. Where the lock allows only one thread to access the value at a time, volatile allows multiple threads to perform read operations, so when using the volatile guarantee to read the code path, it is much more shared-as in read-write operations-than using locks to execute all code paths. However, it is important to keep in mind the weaknesses of this model: if you go beyond the most basic application of the pattern, it will beco

course, to respond to reader and writer changes Public classReader extends Thread {Privatebufferinterruptibly Buff; PublicReader (bufferinterruptibly buff) { This. Buff =Buff; } @Override Public voidrun () {Try{buff.read ();//can receive an interrupt exception to effectively exit}Catch(interruptedexception e) {System. out. println ("I'm not reading."); } System. out. println ("Read End"); } } Public classWriter extends Thread {Privatebufferinterruptibly Buff; PublicWriter

AQS 14.6.1 reentrantlock 14.6.2 Sem Aphore and Countdownlatch 14.6.3 futuretask 14.6.4 reentrantreadwritelockthe 15th chapter atom variable and non-blocking synchronization mechanism15.1 Disadvantages of the lock 15.2 hardware support for concurrency 15.2.1 compare and exchange 15.2.2 non-blocking counters 15.2.3 JVM support for CAS 15.3 atomic variable class 15.3.1 atomic variable is a "better volatile" 1 5.3.2 Performance Comparison: Lock and Atom

Java.util.concurrent.threadpoolexecutor$worker.run (Unknown Source)At Java.lang.Thread.run (Unknown Source)t:6,i:0, tid:15Exception in thread ' pool-1-thread-6 ' Exception in thread ' pool-1-thread-5 ' Exception in thread ' pool-1-thread-7 ' java . lang. ArithmeticException:/by zeroAt Com.test.concurrence.threadpooltest$3.run (threadpooltest.java:58)At Java.util.concurrent.ThreadPoolExecutor.runWorker (Unknown Source)At Java.util.concurrent.threadpoo

threads in the thread pool is greater than corepoolsize, until the number of threads in the thread pool is not greater than corepoolsize, that is, when the number of threads in the thread pool is greater than corepoolsize. If a thread is idle for KeepAliveTime, it terminates until the number of threads in the thread pool does not exceed corepoolsize. However, if the Allowcorethreadtimeout (Boolean) method is called and the number of threads in the thread pool is not greater than corepoolsize, t

to ensure that the log service would eventually shut down before the JVM stopped, even if the caller did not call the Stop method to halt the log service;Here's a quick introduction to closing the hooks:Closing a hook is a thread that is registered through the Runtime.addshutdown method but does not start the task immediately, and the JVM starts execution of the closed hook thread that has already been registered during the shutdown process. Closing a hook is typically used to clean up a servic

Tag:perlhome Read blogshared write gray read lock family technology sharing Java Concurrency Programming: Concurrent lock mechanism parsing table of Contents 1. Lock 2. Reentrantlock 3. Readwritelock 4. Reentrantreadwritelock Earlier, we talked about the object lock mechanism that comes with Java