mastering concurrency programming with java 8

FinalInteger index = 5000;//the cardinality of the split task Private FinalInteger left; Private FinalInteger right; PublicFockJoin1 (integer left, integer right) { This. left =Left ; This. right =Right ; } @OverrideprotectedInteger Compute () {intsum = 0; if(Right-left //if the task is less than the cardinality, it is executed directly; like a recursive exit for(inti = left; I ) {sum+=i; } }Else{//tasks larger than cardinality, then split, similar to dichotomy, can also

creating many threads to handle, resulting in a large number of threads waiting (waiting).Co-process: Multi-tasking scheduling in single thread, and the switch between multiple tasks in a single thread.Hardware resources limit the bandwidth of upload/download speed, hard disk read and write speed and CPU processing speed. Software resources limit the number of connections to the database and socket connections.How can i solve the problem of resource limitations? For hardware limitation

can call interrupted or isinterrupted at the appropriate time to detect the state and do the appropriate processing.>> interrupted usage scenariosInterrupt usage scenarios typically include the following:When you click the Cancel button in a desktop app;An operation exceeds a certain execution time limit when it needs to be aborted;Multiple threads do the same thing, as long as a thread succeeds when other threads can be canceled;When one or more errors in a group of threads cause an entire gro

Chapter 3rd: Sharing of objects The understanding of the volatile keyword a volatile variable that is used to ensure that a variable's row action is notified to other threads. When a variable is declared as a volatile type, the compiler and the runtime will notice that the variable is shared, so the operation on that variable is not reordered with other memory operations. Volatile variables are not cached to registers or other processors where they are not visible, so the most rece

It is easy to start tasks and threads. However, sometimes we want to end a task or thread prematurely, perhaps because the user canceled the operation, or the application needs to be shut down quickly.It's not easy to get tasks and threads to stop safely/quickly/reliably. Java does not provide any mechanism to safely terminate a thread, but it provides interrupts, a collaborative mechanism that enables one thread to terminate the work of another threa

Package Com.chinamobile.epic.tako.common.graphite.query.sync.impl;import Com.google.common.collect.lists;import Java.util.list;import Java.util.concurrent.forkjoinpool;import Java.util.concurrent.forkjointask;import Java.util.concurrent.recursivetask;import Java.util.concurrent.timeunit;public class GraphiteQueryTask extends recursivetaskHttp://www.baeldung.com/java-fork-join"Fork/join" Java

NewIllegalArgumentException (...); lower = value; } Public void Setupper(intValue) {if(Value Throw NewIllegalArgumentException (...); upper = value; } }This approach restricts the state variables of the scope, so defining the lower and upper fields as volatile types does not fully implement the thread safety of the class, so synchronization is still required. Otherwise, if it happens that two threads execute Setlower and setupper at the same time using inconsistent val

elements to the queue is "C", "A", "B", and the Order of removal is "a", "B", "C", which can be seen by the nature of its "precedence".SummarizeThis article introduces three commonly used tool classes, threadlocal is used to solve the problem of multi-threaded sharing the same variable, it is equivalent to creating a thread object as a key to the target object as a value of a map, but actually and map is different, For example, a map object does not garbage-reclaims the corresponding value afte

make Mutableinteger a thread-safe class, as follows:[Java]View Plaincopy public class synchronizedinteger {NBSP;NBSP; private int value; NBSP;NBSP; public synchronized NBSP; int get () { return value; } PublicsynchronizedvoidSet (intvalue) { this } } The set and get methods are synchronized, with the same object lock, so that the Get method can see the change in the value of the set

. If a read thread attempts to acquire a write lock, it will not succeed.Lock downgradingReentrancy also allows downgrading from the write lock to a read lock, by acquiring the write lock, then the read lock and Then releasing the write lock. However, upgrading from a read lock to the write lock are not possible.ChineseLock downgradeBy acquiring a write lock, acquiring a read lock, and then releasing the write lock, Reentrant also allows the downgrade from a write lock to a read lock. However, i

completed: Number of threads in 0--thread pool: 5--Number of threads in the column: 4--Number of threads executed: 0--thread pool: 5--Number of threads in the column: 5--Number of threads executed: 0--threads in thread pool: 6--Number of threads in the column: 5 --Number of threads executed: 0thread Start, Thread:11--threads in thread pool: 7--Number of threads in the column: 5--Number of threads executed: 0thread Start, Thread:12--threads in thread pool: 8