public class ThreadPoolExecutor extends AbstractExecutorService
ExecutorService that executes each submitted task using
 one of possibly several pooled threads, normally configured
 using Executors factory methods.
 Thread pools address two different problems: they usually
 provide improved performance when executing large numbers of
 asynchronous tasks, due to reduced per-task invocation overhead,
 and they provide a means of bounding and managing the resources,
 including threads, consumed when executing a collection of tasks.
 Each ThreadPoolExecutor also maintains some basic
 statistics, such as the number of completed tasks.
 
To be useful across a wide range of contexts, this class
 provides many adjustable parameters and extensibility
 hooks. However, programmers are urged to use the more convenient
 Executors factory methods Executors.newCachedThreadPool() (unbounded thread pool, with
 automatic thread reclamation), Executors.newFixedThreadPool(int)
 (fixed size thread pool) and Executors.newSingleThreadExecutor() (single background thread), that
 preconfigure settings for the most common usage
 scenarios. Otherwise, use the following guide when manually
 configuring and tuning this class:
 
ThreadPoolExecutor will automatically adjust the
 pool size (see getPoolSize())
 according to the bounds set by
 corePoolSize (see getCorePoolSize()) and
 maximumPoolSize (see getMaximumPoolSize()).
 When a new task is submitted in method execute(Runnable),
 and fewer than corePoolSize threads are running, a new thread is
 created to handle the request, even if other worker threads are
 idle.  If there are more than corePoolSize but less than
 maximumPoolSize threads running, a new thread will be created only
 if the queue is full.  By setting corePoolSize and maximumPoolSize
 the same, you create a fixed-size thread pool. By setting
 maximumPoolSize to an essentially unbounded value such as Integer.MAX_VALUE, you allow the pool to accommodate an arbitrary
 number of concurrent tasks. Most typically, core and maximum pool
 sizes are set only upon construction, but they may also be changed
 dynamically using setCorePoolSize(int) and setMaximumPoolSize(int). prestartCoreThread() or prestartAllCoreThreads().  You probably want to prestart threads if
 you construct the pool with a non-empty queue. ThreadFactory.  If not
 otherwise specified, a Executors.defaultThreadFactory() is
 used, that creates threads to all be in the same ThreadGroup and with the same NORM_PRIORITY priority and
 non-daemon status. By supplying a different ThreadFactory, you can
 alter the thread's name, thread group, priority, daemon status,
 etc. If a ThreadFactory fails to create a thread when asked
 by returning null from newThread, the executor will
 continue, but might not be able to execute any tasks. Threads
 should possess the "modifyThread" RuntimePermission. If
 worker threads or other threads using the pool do not possess this
 permission, service may be degraded: configuration changes may not
 take effect in a timely manner, and a shutdown pool may remain in a
 state in which termination is possible but not completed.getKeepAliveTime(TimeUnit)).
 This provides a means of reducing resource consumption when the
 pool is not being actively used. If the pool becomes more active
 later, new threads will be constructed. This parameter can also be
 changed dynamically using method setKeepAliveTime(long,
 TimeUnit).  Using a value of Long.MAX_VALUE TimeUnit.NANOSECONDS effectively disables idle threads from ever
 terminating prior to shut down. By default, the keep-alive policy
 applies only when there are more than corePoolSize threads. But
 method allowCoreThreadTimeOut(boolean) can be used to
 apply this time-out policy to core threads as well, so long as the
 keepAliveTime value is non-zero. BlockingQueue may be used to transfer and hold
 submitted tasks.  The use of this queue interacts with pool sizing:
 SynchronousQueue that hands off tasks to threads
 without otherwise holding them. Here, an attempt to queue a task
 will fail if no threads are immediately available to run it, so a
 new thread will be constructed. This policy avoids lockups when
 handling sets of requests that might have internal dependencies.
 Direct handoffs generally require unbounded maximumPoolSizes to
 avoid rejection of new submitted tasks. This in turn admits the
 possibility of unbounded thread growth when commands continue to
 arrive on average faster than they can be processed.  LinkedBlockingQueue without a predefined
 capacity) will cause new tasks to wait in the queue when all
 corePoolSize threads are busy. Thus, no more than corePoolSize
 threads will ever be created. (And the value of the maximumPoolSize
 therefore doesn't have any effect.)  This may be appropriate when
 each task is completely independent of others, so tasks cannot
 affect each others execution; for example, in a web page server.
 While this style of queuing can be useful in smoothing out
 transient bursts of requests, it admits the possibility of
 unbounded work queue growth when commands continue to arrive on
 average faster than they can be processed.  ArrayBlockingQueue) helps prevent resource exhaustion when
 used with finite maximumPoolSizes, but can be more difficult to
 tune and control.  Queue sizes and maximum pool sizes may be traded
 off for each other: Using large queues and small pools minimizes
 CPU usage, OS resources, and context-switching overhead, but can
 lead to artificially low throughput.  If tasks frequently block (for
 example if they are I/O bound), a system may be able to schedule
 time for more threads than you otherwise allow. Use of small queues
 generally requires larger pool sizes, which keeps CPUs busier but
 may encounter unacceptable scheduling overhead, which also
 decreases throughput.  execute(Runnable) will be
 rejected when the Executor has been shut down, and also when
 the Executor uses finite bounds for both maximum threads and work queue
 capacity, and is saturated.  In either case, the execute method
 invokes the RejectedExecutionHandler.rejectedExecution(Runnable, ThreadPoolExecutor)
 method of its RejectedExecutionHandler.  Four predefined handler
 policies are provided:
 ThreadPoolExecutor.AbortPolicy, the
 handler throws a runtime RejectedExecutionException upon
 rejection. ThreadPoolExecutor.CallerRunsPolicy, the thread
 that invokes execute itself runs the task. This provides a
 simple feedback control mechanism that will slow down the rate that
 new tasks are submitted. ThreadPoolExecutor.DiscardPolicy, a task that
 cannot be executed is simply dropped.  ThreadPoolExecutor.DiscardOldestPolicy, if the
 executor is not shut down, the task at the head of the work queue
 is dropped, and then execution is retried (which can fail again,
 causing this to be repeated.) RejectedExecutionHandler classes. Doing so requires some care
 especially when policies are designed to work only under particular
 capacity or queuing policies. protected overridable
 beforeExecute(Thread, Runnable) and
 afterExecute(Runnable, Throwable) methods that are called
 before and after execution of each task.  These can be used to
 manipulate the execution environment; for example, reinitializing
 ThreadLocals, gathering statistics, or adding log entries.
 Additionally, method terminated() can be overridden to perform
 any special processing that needs to be done once the Executor has
 fully terminated.
 If hook or callback methods throw exceptions, internal worker threads may in turn fail and abruptly terminate.
getQueue() allows access to the work queue
 for purposes of monitoring and debugging.  Use of this method for
 any other purpose is strongly discouraged.  Two supplied methods,
 remove(Runnable) and purge() are available to
 assist in storage reclamation when large numbers of queued tasks
 become cancelled.shutdown automatically. If
 you would like to ensure that unreferenced pools are reclaimed even
 if users forget to call shutdown(), then you must arrange
 that unused threads eventually die, by setting appropriate
 keep-alive times, using a lower bound of zero core threads and/or
 setting allowCoreThreadTimeOut(boolean).  Extension example. Most extensions of this class override one or more of the protected hook methods. For example, here is a subclass that adds a simple pause/resume feature:
 
 class PausableThreadPoolExecutor extends ThreadPoolExecutor {
   private boolean isPaused;
   private ReentrantLock pauseLock = new ReentrantLock();
   private Condition unpaused = pauseLock.newCondition();
   public PausableThreadPoolExecutor(...) { super(...); }
   protected void beforeExecute(Thread t, Runnable r) {
     super.beforeExecute(t, r);
     pauseLock.lock();
     try {
       while (isPaused) unpaused.await();
     } catch (InterruptedException ie) {
       t.interrupt();
     } finally {
       pauseLock.unlock();
     }
   }
   public void pause() {
     pauseLock.lock();
     try {
       isPaused = true;
     } finally {
       pauseLock.unlock();
     }
   }
   public void resume() {
     pauseLock.lock();
     try {
       isPaused = false;
       unpaused.signalAll();
     } finally {
       pauseLock.unlock();
     }
   }
 }| Modifier and Type | Class and Description | 
|---|---|
| static class  | ThreadPoolExecutor.AbortPolicyA handler for rejected tasks that throws a
  RejectedExecutionException. | 
| static class  | ThreadPoolExecutor.CallerRunsPolicyA handler for rejected tasks that runs the rejected task
 directly in the calling thread of the  executemethod,
 unless the executor has been shut down, in which case the task
 is discarded. | 
| static class  | ThreadPoolExecutor.DiscardOldestPolicyA handler for rejected tasks that discards the oldest unhandled
 request and then retries  execute, unless the executor
 is shut down, in which case the task is discarded. | 
| static class  | ThreadPoolExecutor.DiscardPolicyA handler for rejected tasks that silently discards the
 rejected task. | 
| Constructor and Description | 
|---|
| ThreadPoolExecutor(int corePoolSize,
                  int maximumPoolSize,
                  long keepAliveTime,
                  TimeUnit unit,
                  BlockingQueue<Runnable> workQueue)Creates a new  ThreadPoolExecutorwith the given initial
 parameters and default thread factory and rejected execution handler. | 
| ThreadPoolExecutor(int corePoolSize,
                  int maximumPoolSize,
                  long keepAliveTime,
                  TimeUnit unit,
                  BlockingQueue<Runnable> workQueue,
                  RejectedExecutionHandler handler)Creates a new  ThreadPoolExecutorwith the given initial
 parameters and default thread factory. | 
| ThreadPoolExecutor(int corePoolSize,
                  int maximumPoolSize,
                  long keepAliveTime,
                  TimeUnit unit,
                  BlockingQueue<Runnable> workQueue,
                  ThreadFactory threadFactory)Creates a new  ThreadPoolExecutorwith the given initial
 parameters and default rejected execution handler. | 
| ThreadPoolExecutor(int corePoolSize,
                  int maximumPoolSize,
                  long keepAliveTime,
                  TimeUnit unit,
                  BlockingQueue<Runnable> workQueue,
                  ThreadFactory threadFactory,
                  RejectedExecutionHandler handler)Creates a new  ThreadPoolExecutorwith the given initial
 parameters. | 
| Modifier and Type | Method and Description | 
|---|---|
| protected void | afterExecute(Runnable r,
            Throwable t)Method invoked upon completion of execution of the given Runnable. | 
| void | allowCoreThreadTimeOut(boolean value)Sets the policy governing whether core threads may time out and
 terminate if no tasks arrive within the keep-alive time, being
 replaced if needed when new tasks arrive. | 
| boolean | allowsCoreThreadTimeOut()Returns true if this pool allows core threads to time out and
 terminate if no tasks arrive within the keepAlive time, being
 replaced if needed when new tasks arrive. | 
| boolean | awaitTermination(long timeout,
                TimeUnit unit)Blocks until all tasks have completed execution after a shutdown
 request, or the timeout occurs, or the current thread is
 interrupted, whichever happens first. | 
| protected void | beforeExecute(Thread t,
             Runnable r)Method invoked prior to executing the given Runnable in the
 given thread. | 
| void | execute(Runnable command)Executes the given task sometime in the future. | 
| protected void | finalize()Invokes  shutdownwhen this executor is no longer
 referenced and it has no threads. | 
| int | getActiveCount()Returns the approximate number of threads that are actively
 executing tasks. | 
| long | getCompletedTaskCount()Returns the approximate total number of tasks that have
 completed execution. | 
| int | getCorePoolSize()Returns the core number of threads. | 
| long | getKeepAliveTime(TimeUnit unit)Returns the thread keep-alive time, which is the amount of time
 that threads in excess of the core pool size may remain
 idle before being terminated. | 
| int | getLargestPoolSize()Returns the largest number of threads that have ever
 simultaneously been in the pool. | 
| int | getMaximumPoolSize()Returns the maximum allowed number of threads. | 
| int | getPoolSize()Returns the current number of threads in the pool. | 
| BlockingQueue<Runnable> | getQueue()Returns the task queue used by this executor. | 
| RejectedExecutionHandler | getRejectedExecutionHandler()Returns the current handler for unexecutable tasks. | 
| long | getTaskCount()Returns the approximate total number of tasks that have ever been
 scheduled for execution. | 
| ThreadFactory | getThreadFactory()Returns the thread factory used to create new threads. | 
| boolean | isShutdown()Returns  trueif this executor has been shut down. | 
| boolean | isTerminated()Returns  trueif all tasks have completed following shut down. | 
| boolean | isTerminating()Returns true if this executor is in the process of terminating
 after  shutdown()orshutdownNow()but has not
 completely terminated. | 
| int | prestartAllCoreThreads()Starts all core threads, causing them to idly wait for work. | 
| boolean | prestartCoreThread()Starts a core thread, causing it to idly wait for work. | 
| void | purge()Tries to remove from the work queue all  Futuretasks that have been cancelled. | 
| boolean | remove(Runnable task)Removes this task from the executor's internal queue if it is
 present, thus causing it not to be run if it has not already
 started. | 
| void | setCorePoolSize(int corePoolSize)Sets the core number of threads. | 
| void | setKeepAliveTime(long time,
                TimeUnit unit)Sets the time limit for which threads may remain idle before
 being terminated. | 
| void | setMaximumPoolSize(int maximumPoolSize)Sets the maximum allowed number of threads. | 
| void | setRejectedExecutionHandler(RejectedExecutionHandler handler)Sets a new handler for unexecutable tasks. | 
| void | setThreadFactory(ThreadFactory threadFactory)Sets the thread factory used to create new threads. | 
| void | shutdown()Initiates an orderly shutdown in which previously submitted
 tasks are executed, but no new tasks will be accepted. | 
| List<Runnable> | shutdownNow()Attempts to stop all actively executing tasks, halts the
 processing of waiting tasks, and returns a list of the tasks
 that were awaiting execution. | 
| protected void | terminated()Method invoked when the Executor has terminated. | 
| String | toString()Returns a string identifying this pool, as well as its state,
 including indications of run state and estimated worker and
 task counts. | 
invokeAll, invokeAll, invokeAny, invokeAny, newTaskFor, newTaskFor, submit, submit, submitpublic ThreadPoolExecutor(int corePoolSize,
                          int maximumPoolSize,
                          long keepAliveTime,
                          TimeUnit unit,
                          BlockingQueue<Runnable> workQueue)
ThreadPoolExecutor with the given initial
 parameters and default thread factory and rejected execution handler.
 It may be more convenient to use one of the Executors factory
 methods instead of this general purpose constructor.corePoolSize - the number of threads to keep in the pool, even
        if they are idle, unless allowCoreThreadTimeOut is setmaximumPoolSize - the maximum number of threads to allow in the
        poolkeepAliveTime - when the number of threads is greater than
        the core, this is the maximum time that excess idle threads
        will wait for new tasks before terminating.unit - the time unit for the keepAliveTime argumentworkQueue - the queue to use for holding tasks before they are
        executed.  This queue will hold only the Runnable
        tasks submitted by the execute method.IllegalArgumentException - if one of the following holds:corePoolSize < 0keepAliveTime < 0maximumPoolSize <= 0maximumPoolSize < corePoolSizeNullPointerException - if workQueue is nullpublic ThreadPoolExecutor(int corePoolSize,
                          int maximumPoolSize,
                          long keepAliveTime,
                          TimeUnit unit,
                          BlockingQueue<Runnable> workQueue,
                          ThreadFactory threadFactory)
ThreadPoolExecutor with the given initial
 parameters and default rejected execution handler.corePoolSize - the number of threads to keep in the pool, even
        if they are idle, unless allowCoreThreadTimeOut is setmaximumPoolSize - the maximum number of threads to allow in the
        poolkeepAliveTime - when the number of threads is greater than
        the core, this is the maximum time that excess idle threads
        will wait for new tasks before terminating.unit - the time unit for the keepAliveTime argumentworkQueue - the queue to use for holding tasks before they are
        executed.  This queue will hold only the Runnable
        tasks submitted by the execute method.threadFactory - the factory to use when the executor
        creates a new threadIllegalArgumentException - if one of the following holds:corePoolSize < 0keepAliveTime < 0maximumPoolSize <= 0maximumPoolSize < corePoolSizeNullPointerException - if workQueue
         or threadFactory is nullpublic ThreadPoolExecutor(int corePoolSize,
                          int maximumPoolSize,
                          long keepAliveTime,
                          TimeUnit unit,
                          BlockingQueue<Runnable> workQueue,
                          RejectedExecutionHandler handler)
ThreadPoolExecutor with the given initial
 parameters and default thread factory.corePoolSize - the number of threads to keep in the pool, even
        if they are idle, unless allowCoreThreadTimeOut is setmaximumPoolSize - the maximum number of threads to allow in the
        poolkeepAliveTime - when the number of threads is greater than
        the core, this is the maximum time that excess idle threads
        will wait for new tasks before terminating.unit - the time unit for the keepAliveTime argumentworkQueue - the queue to use for holding tasks before they are
        executed.  This queue will hold only the Runnable
        tasks submitted by the execute method.handler - the handler to use when execution is blocked
        because the thread bounds and queue capacities are reachedIllegalArgumentException - if one of the following holds:corePoolSize < 0keepAliveTime < 0maximumPoolSize <= 0maximumPoolSize < corePoolSizeNullPointerException - if workQueue
         or handler is nullpublic ThreadPoolExecutor(int corePoolSize,
                          int maximumPoolSize,
                          long keepAliveTime,
                          TimeUnit unit,
                          BlockingQueue<Runnable> workQueue,
                          ThreadFactory threadFactory,
                          RejectedExecutionHandler handler)
ThreadPoolExecutor with the given initial
 parameters.corePoolSize - the number of threads to keep in the pool, even
        if they are idle, unless allowCoreThreadTimeOut is setmaximumPoolSize - the maximum number of threads to allow in the
        poolkeepAliveTime - when the number of threads is greater than
        the core, this is the maximum time that excess idle threads
        will wait for new tasks before terminating.unit - the time unit for the keepAliveTime argumentworkQueue - the queue to use for holding tasks before they are
        executed.  This queue will hold only the Runnable
        tasks submitted by the execute method.threadFactory - the factory to use when the executor
        creates a new threadhandler - the handler to use when execution is blocked
        because the thread bounds and queue capacities are reachedIllegalArgumentException - if one of the following holds:corePoolSize < 0keepAliveTime < 0maximumPoolSize <= 0maximumPoolSize < corePoolSizeNullPointerException - if workQueue
         or threadFactory or handler is nullpublic void execute(Runnable command)
RejectedExecutionHandler.command - the task to executeRejectedExecutionException - at discretion of
         RejectedExecutionHandler, if the task
         cannot be accepted for executionNullPointerException - if command is nullpublic void shutdown()
This method does not wait for previously submitted tasks to
 complete execution.  Use awaitTermination
 to do that.
SecurityException - if a security manager exists and
         shutting down this ExecutorService may manipulate
         threads that the caller is not permitted to modify
         because it does not hold RuntimePermission("modifyThread"),
         or the security manager's checkAccess method
         denies access.public List<Runnable> shutdownNow()
This method does not wait for actively executing tasks to
 terminate.  Use awaitTermination to
 do that.
 
There are no guarantees beyond best-effort attempts to stop
 processing actively executing tasks.  This implementation
 cancels tasks via Thread.interrupt(), so any task that
 fails to respond to interrupts may never terminate.
SecurityException - if a security manager exists and
         shutting down this ExecutorService may manipulate
         threads that the caller is not permitted to modify
         because it does not hold RuntimePermission("modifyThread"),
         or the security manager's checkAccess method
         denies access.public boolean isShutdown()
ExecutorServicetrue if this executor has been shut down.true if this executor has been shut downpublic boolean isTerminating()
shutdown() or shutdownNow() but has not
 completely terminated.  This method may be useful for
 debugging. A return of true reported a sufficient
 period after shutdown may indicate that submitted tasks have
 ignored or suppressed interruption, causing this executor not
 to properly terminate.true if terminating but not yet terminatedpublic boolean isTerminated()
ExecutorServicetrue if all tasks have completed following shut down.
 Note that isTerminated is never true unless
 either shutdown or shutdownNow was called first.true if all tasks have completed following shut downpublic boolean awaitTermination(long timeout,
                                TimeUnit unit)
                         throws InterruptedException
ExecutorServicetimeout - the maximum time to waitunit - the time unit of the timeout argumenttrue if this executor terminated and
         false if the timeout elapsed before terminationInterruptedException - if interrupted while waitingprotected void finalize()
shutdown when this executor is no longer
 referenced and it has no threads.finalize in class ObjectWeakReference, 
PhantomReferencepublic void setThreadFactory(ThreadFactory threadFactory)
threadFactory - the new thread factoryNullPointerException - if threadFactory is nullgetThreadFactory()public ThreadFactory getThreadFactory()
setThreadFactory(ThreadFactory)public void setRejectedExecutionHandler(RejectedExecutionHandler handler)
handler - the new handlerNullPointerException - if handler is nullgetRejectedExecutionHandler()public RejectedExecutionHandler getRejectedExecutionHandler()
setRejectedExecutionHandler(RejectedExecutionHandler)public void setCorePoolSize(int corePoolSize)
corePoolSize - the new core sizeIllegalArgumentException - if corePoolSize < 0getCorePoolSize()public int getCorePoolSize()
setCorePoolSize(int)public boolean prestartCoreThread()
false
 if all core threads have already been started.true if a thread was startedpublic int prestartAllCoreThreads()
public boolean allowsCoreThreadTimeOut()
true if core threads are allowed to time out,
         else falsepublic void allowCoreThreadTimeOut(boolean value)
true. This method
 should in general be called before the pool is actively used.value - true if should time out, else falseIllegalArgumentException - if value is true
         and the current keep-alive time is not greater than zeropublic void setMaximumPoolSize(int maximumPoolSize)
maximumPoolSize - the new maximumIllegalArgumentException - if the new maximum is
         less than or equal to zero, or
         less than the core pool sizegetMaximumPoolSize()public int getMaximumPoolSize()
setMaximumPoolSize(int)public void setKeepAliveTime(long time,
                             TimeUnit unit)
time - the time to wait.  A time value of zero will cause
        excess threads to terminate immediately after executing tasks.unit - the time unit of the time argumentIllegalArgumentException - if time less than zero or
         if time is zero and allowsCoreThreadTimeOutgetKeepAliveTime(TimeUnit)public long getKeepAliveTime(TimeUnit unit)
unit - the desired time unit of the resultsetKeepAliveTime(long, TimeUnit)public BlockingQueue<Runnable> getQueue()
public boolean remove(Runnable task)
This method may be useful as one part of a cancellation
 scheme.  It may fail to remove tasks that have been converted
 into other forms before being placed on the internal queue. For
 example, a task entered using submit might be
 converted into a form that maintains Future status.
 However, in such cases, method purge() may be used to
 remove those Futures that have been cancelled.
task - the task to removetrue if the task was removedpublic void purge()
Future
 tasks that have been cancelled. This method can be useful as a
 storage reclamation operation, that has no other impact on
 functionality. Cancelled tasks are never executed, but may
 accumulate in work queues until worker threads can actively
 remove them. Invoking this method instead tries to remove them now.
 However, this method may fail to remove tasks in
 the presence of interference by other threads.public int getPoolSize()
public int getActiveCount()
public int getLargestPoolSize()
public long getTaskCount()
public long getCompletedTaskCount()
public String toString()
protected void beforeExecute(Thread t, Runnable r)
t that
 will execute task r, and may be used to re-initialize
 ThreadLocals, or to perform logging.
 This implementation does nothing, but may be customized in
 subclasses. Note: To properly nest multiple overridings, subclasses
 should generally invoke super.beforeExecute at the end of
 this method.
t - the thread that will run task rr - the task that will be executedprotected void afterExecute(Runnable r, Throwable t)
RuntimeException
 or Error that caused execution to terminate abruptly.
 This implementation does nothing, but may be customized in
 subclasses. Note: To properly nest multiple overridings, subclasses
 should generally invoke super.afterExecute at the
 beginning of this method.
 
Note: When actions are enclosed in tasks (such as
 FutureTask) either explicitly or via methods such as
 submit, these task objects catch and maintain
 computational exceptions, and so they do not cause abrupt
 termination, and the internal exceptions are not
 passed to this method. If you would like to trap both kinds of
 failures in this method, you can further probe for such cases,
 as in this sample subclass that prints either the direct cause
 or the underlying exception if a task has been aborted:
  
 
 class ExtendedExecutor extends ThreadPoolExecutor {
   // ...
   protected void afterExecute(Runnable r, Throwable t) {
     super.afterExecute(r, t);
     if (t == null && r instanceof Future<?>) {
       try {
         Object result = ((Future<?>) r).get();
       } catch (CancellationException ce) {
           t = ce;
       } catch (ExecutionException ee) {
           t = ee.getCause();
       } catch (InterruptedException ie) {
           Thread.currentThread().interrupt(); // ignore/reset
       }
     }
     if (t != null)
       System.out.println(t);
   }
 }r - the runnable that has completedt - the exception that caused termination, or null if
 execution completed normallyprotected void terminated()
super.terminated within this method. Submit a bug or feature 
For further API reference and developer documentation, see Java SE Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.
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