java concurrency in practice 2nd edition

In the Java Concurrency Programming practice, 4.4 mentions the method of locking the client. This is a validation example, but it is not good to write, but you can see the result. Packagecom.blackbread.test;Importjava.util.ArrayList;Importjava.util.Collections;Importjava.util.List;ImportJava.util.concurrent.ExecutorService;Importjava.util.concurrent.Executors; Pu

technologies, there is no need to download plugins or small programs.Ajax has a lot of merit, and it is these strengths that reflect its shortcomings (of course, the shortcomings can be overcome).Disadvantages:1. Security issues2. Support for search engines is relatively weak.3. The exception handling mechanism of the program is broken.4. The original intention of URL and resource location is violated.Actual combata simple, but useful example: TheJava version asynchronously verifies that userna

to be met, simplicity, and performance. There is often a mutual constraint between simplicity and performance. When implementing a synchronization strategy, be sure not to blindly sacrifice simplicity for performance (which could compromise security). When using a lock, you should be aware of the functionality implemented in the code block and whether it will take a long time to execute the code block. Whether you are performing a computationally intensive operation or performing

Plan to write a "Java Concurrent basic Practice" series, counted as my Java concurrency Learning and practice of a simple summary. This is the first of the series that describes the easiest way to quit a concurrent task. After a concurrent task is started, do not expect it

The synchronized keyword provided by Java provides thread-synchronous access to critical sections. Because it is difficult to synchronized basedThe synchronization code is written correctly, and the Concurrency tool class provides an advanced Synchronizer. Countdown latch (countdown latch), Sync screen(cyclic barrier), switch (exchanger), Semaphore (semaphore), and Phaser Synchronizer. The following mainInt

is compared, if the same, it means that there has not been a write operation, the result of the original traversal is returned, if not the same, the process is repeated again, if not the same, It is necessary to lock all the segment and then one through. Public intsize () {//Try a few times to get accurate count. On failure due to//continuous async changes in table, resort to locking. FinalSegment This. Segments; intsize; BooleanOverflow//true if size overflows LongSum//Sum of mo

. If operation A is performed before action B and action B is performed before Operation C, then operation a must be performed before Operation C.The following is an English description of happens-before,the Happens-before relation defines when data races take place. An unlock in a monitor happens-before every subsequent lock on the that monitor. A write to a volatile field happens-before every subsequent read of the that field. A call to start () on a thre

EXEC2 =NewWithinthreadexecutor (); Public Static voidMain (string[] args)throwsIOException {serversocket socket=NewServerSocket (80); while(true) { FinalSocket connection =socket.accept (); Runnable Task=NewRunnable () { Public voidrun () {//HandleRequest (connection); } }; Exec.execute (Task); } }}classThreadpertaskexecutorImplementsExecutor { Public voidExecute (Runnable r) {NewThread (R). Start (); };}classWithinthreadexecutorImplementsExecuto

Similar to the multi-tasking scenario of a Web server, it is not possible to use only one thread to provide services externally. This way, efficiency and throughput are too low.However, it is not possible to create a thread with a single request because the cost of creating the thread is very high and the number of threads that the system can create is limited.So the executor appeared.The meaning of executor frame thread poolThread creation too little wasted server resources, in addition to the

provides a useful set of low-level synchronization primitives: Wait (), notify (), and synchronized, but the specific use of these primitives requires some skill, including performance, deadlock, fairness, resource management, and how to avoid the hazards of thread security. Concurrent code is difficult to write and more difficult to test-even if an expert sometimes gets an error at the first time. Doug Lea, author of Concurrent programming in Java (

to define more information that you need.Extended ThreadpoolexecutorThreadpoolexecutor has some life cycle methods: BeforeExecute, AfterExecute, and terminated. These methods can be overridden to implement statistical and monitoring functions.The parallelization of recursive algorithmWhat kind of situation can be parallel?For example, for the loop to do something, and these things are independent of each other. Then these things can actually be done in parallel (for loop is serial execution).Th

data:imagedatas) {renderimage (data);//working with pictures } } Catch(Interruptedexception |executionexception e) { //TODO auto-generated Catch blockE.printstacktrace (); } }}This execution strategy still has limitations, because running heterogeneous tasks in parallel does not get good performance. Only a large number of independent and homogeneous tasks can be processed concurrently to achieve real performance gains.3. Third Way: Using the Completionservice pa

Exercise 1: (1) Create a class in a package that creates an instance of the class outside the package where the class is located.Import Mil.oms.main.test.Test; Public class maintest {public static void Main (String args[]) { Test test=new test (); } /** Run result test () instantiation ... Package Mil.oms.main.test;public class Test{public Test () {System.out.println ("Test () instantiation ...");}Exercise 2: (1) rewrite the code snippet in this section as a c

Frame1_jbutton2_actionadapter (this)); Jlabel2.settext ("First off: 10"); Jlabel2.setbounds (New Rectangle (414, 473, 171, 21)); Contentpane.add (JPANEL1); Contentpane.add (JButton2); Contentpane.add (JButton1); Contentpane.add (JSlider1); Contentpane.add (JLABEL1); Contentpane.add (JLABEL2); This.addkeylistener (New MyListener ()); Jbutton1.addkeylistener (Ne

Frame1_jbutton2_actionadapter (this)); Jlabel2.settext ("First off: 10"); Jlabel2.setbounds (New Rectangle (414, 473, 171, 21)); Contentpane.add (JPANEL1); Contentpane.add (JButton2); Contentpane.add (JButton1); Contentpane.add (JSlider1); Contentpane.add (JLABEL1); Contentpane.add (JLABEL2); This.addkeylistener (New MyListener ()); Jbutton1.addkeylistener (Ne

==N2) + "\ T" + "N1Exercise 4: (3) write a program that uses two nested for loops and the remainder operator (%) to detect and print a prime number (an integer that can be divisible only by itself and 1 and not by other numbers). public static void Main (string[] args) {test (33);} public static Boolean test (int num) {for (int i=2;iExercise 5: (4) Repeat Exercise 10 in chapter 3rd, instead of using the integer.tobinarystring () method, use the ternary and bitwise operators to display the

Exercise 3: (1) Create a class with a default constructor (that is, a parameterless constructor) to print a message in the constructor. Create an object for this class. P116public class Test{public Test () {System.out.println ("Hello Word");} public static void Main (string[] args) {new Test ();} /** * Run result Hello Word */}Exercise 4: (1) Add an overloaded constructor to the class in the previous exercise so that it accepts a character parameter and prints your own information and accepted p