ScheduledThreadPoolExecutor (Java 2 Platform SE 5.0) (original) (raw)

java.util.concurrent

Class ScheduledThreadPoolExecutor

java.lang.Object extended by java.util.concurrent.AbstractExecutorService java.util.concurrent.ThreadPoolExecutor java.util.concurrent.ScheduledThreadPoolExecutor

All Implemented Interfaces:

Executor, ExecutorService, ScheduledExecutorService

public class ScheduledThreadPoolExecutor

extends ThreadPoolExecutor

implements ScheduledExecutorService

A ThreadPoolExecutor that can additionally schedule commands to run after a given delay, or to execute periodically. This class is preferable to Timer when multiple worker threads are needed, or when the additional flexibility or capabilities of ThreadPoolExecutor (which this class extends) are required.

Delayed tasks execute no sooner than they are enabled, but without any real-time guarantees about when, after they are enabled, they will commence. Tasks scheduled for exactly the same execution time are enabled in first-in-first-out (FIFO) order of submission.

While this class inherits from ThreadPoolExecutor, a few of the inherited tuning methods are not useful for it. In particular, because it acts as a fixed-sized pool usingcorePoolSize threads and an unbounded queue, adjustments to maximumPoolSize have no useful effect.

Since:

1.5

Nested Class Summary

Nested classes/interfaces inherited from class java.util.concurrent.ThreadPoolExecutor
ThreadPoolExecutor.AbortPolicy, ThreadPoolExecutor.CallerRunsPolicy, ThreadPoolExecutor.DiscardOldestPolicy, ThreadPoolExecutor.DiscardPolicy

Constructor Summary
ScheduledThreadPoolExecutor(int corePoolSize) Creates a new ScheduledThreadPoolExecutor with the given core pool size.
[ScheduledThreadPoolExecutor](../../../java/util/concurrent/ScheduledThreadPoolExecutor.html#ScheduledThreadPoolExecutor%28int, java.util.concurrent.RejectedExecutionHandler%29)(int corePoolSize,RejectedExecutionHandler handler) Creates a new ScheduledThreadPoolExecutor with the given initial parameters.
[ScheduledThreadPoolExecutor](../../../java/util/concurrent/ScheduledThreadPoolExecutor.html#ScheduledThreadPoolExecutor%28int, java.util.concurrent.ThreadFactory%29)(int corePoolSize,ThreadFactory threadFactory) Creates a new ScheduledThreadPoolExecutor with the given initial parameters.
[ScheduledThreadPoolExecutor](../../../java/util/concurrent/ScheduledThreadPoolExecutor.html#ScheduledThreadPoolExecutor%28int, java.util.concurrent.ThreadFactory, java.util.concurrent.RejectedExecutionHandler%29)(int corePoolSize,ThreadFactory threadFactory,RejectedExecutionHandler handler) Creates a new ScheduledThreadPoolExecutor with the given initial parameters.

Method Summary
void	execute(Runnable command) Execute command with zero required delay.
boolean	getContinueExistingPeriodicTasksAfterShutdownPolicy() Get the policy on whether to continue executing existing periodic tasks even when this executor has beenshutdown.
boolean	getExecuteExistingDelayedTasksAfterShutdownPolicy() Get policy on whether to execute existing delayed tasks even when this executor has been shutdown.
BlockingQueue<Runnable>	getQueue() Returns the task queue used by this executor.
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.
ScheduledFuture	[schedule](../../../java/util/concurrent/ScheduledThreadPoolExecutor.html#schedule%28java.util.concurrent.Callable, long, java.util.concurrent.TimeUnit%29)(Callable callable, long delay,TimeUnit unit) Creates and executes a ScheduledFuture that becomes enabled after the given delay.
ScheduledFuture<?>	[schedule](../../../java/util/concurrent/ScheduledThreadPoolExecutor.html#schedule%28java.lang.Runnable, long, java.util.concurrent.TimeUnit%29)(Runnable command, long delay,TimeUnit unit) Creates and executes a one-shot action that becomes enabled after the given delay.
ScheduledFuture<?>	[scheduleAtFixedRate](../../../java/util/concurrent/ScheduledThreadPoolExecutor.html#scheduleAtFixedRate%28java.lang.Runnable, long, long, java.util.concurrent.TimeUnit%29)(Runnable command, long initialDelay, long period,TimeUnit unit) Creates and executes a periodic action that becomes enabled first after the given initial delay, and subsequently with the given period; that is executions will commence afterinitialDelay then initialDelay+period, theninitialDelay + 2 * period, and so on.
ScheduledFuture<?>	[scheduleWithFixedDelay](../../../java/util/concurrent/ScheduledThreadPoolExecutor.html#scheduleWithFixedDelay%28java.lang.Runnable, long, long, java.util.concurrent.TimeUnit%29)(Runnable command, long initialDelay, long delay,TimeUnit unit) Creates and executes a periodic action that becomes enabled first after the given initial delay, and subsequently with the given delay between the termination of one execution and the commencement of the next.
void	setContinueExistingPeriodicTasksAfterShutdownPolicy(boolean value) Set policy on whether to continue executing existing periodic tasks even when this executor has been shutdown.
void	setExecuteExistingDelayedTasksAfterShutdownPolicy(boolean value) Set policy on whether to execute existing delayed tasks even when this executor has been shutdown.
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.
Future	submit(Callable task) Submits a value-returning task for execution and returns a Future representing the pending results of the task.
Future<?>	submit(Runnable task) Submits a Runnable task for execution and returns a Future representing that task.
Future	[submit](../../../java/util/concurrent/ScheduledThreadPoolExecutor.html#submit%28java.lang.Runnable, T%29)(Runnable task, T result) Submits a Runnable task for execution and returns a Future representing that task that will upon completion return the given result

Methods inherited from class java.util.concurrent.ThreadPoolExecutor
[afterExecute](../../../java/util/concurrent/ThreadPoolExecutor.html#afterExecute%28java.lang.Runnable, java.lang.Throwable%29), [awaitTermination](../../../java/util/concurrent/ThreadPoolExecutor.html#awaitTermination%28long, java.util.concurrent.TimeUnit%29), [beforeExecute](../../../java/util/concurrent/ThreadPoolExecutor.html#beforeExecute%28java.lang.Thread, java.lang.Runnable%29), finalize, getActiveCount, getCompletedTaskCount, getCorePoolSize, getKeepAliveTime, getLargestPoolSize, getMaximumPoolSize, getPoolSize, getRejectedExecutionHandler, getTaskCount, getThreadFactory, isShutdown, isTerminated, isTerminating, prestartAllCoreThreads, prestartCoreThread, purge, setCorePoolSize, [setKeepAliveTime](../../../java/util/concurrent/ThreadPoolExecutor.html#setKeepAliveTime%28long, java.util.concurrent.TimeUnit%29), setMaximumPoolSize, setRejectedExecutionHandler, setThreadFactory, terminated

Methods inherited from class java.util.concurrent.ThreadPoolExecutor

[afterExecute](../../../java/util/concurrent/ThreadPoolExecutor.html#afterExecute%28java.lang.Runnable, java.lang.Throwable%29), [awaitTermination](../../../java/util/concurrent/ThreadPoolExecutor.html#awaitTermination%28long, java.util.concurrent.TimeUnit%29), [beforeExecute](../../../java/util/concurrent/ThreadPoolExecutor.html#beforeExecute%28java.lang.Thread, java.lang.Runnable%29), finalize, getActiveCount, getCompletedTaskCount, getCorePoolSize, getKeepAliveTime, getLargestPoolSize, getMaximumPoolSize, getPoolSize, getRejectedExecutionHandler, getTaskCount, getThreadFactory, isShutdown, isTerminated, isTerminating, prestartAllCoreThreads, prestartCoreThread, purge, setCorePoolSize, [setKeepAliveTime](../../../java/util/concurrent/ThreadPoolExecutor.html#setKeepAliveTime%28long, java.util.concurrent.TimeUnit%29), setMaximumPoolSize, setRejectedExecutionHandler, setThreadFactory, terminated

Methods inherited from class java.util.concurrent.AbstractExecutorService
invokeAll, [invokeAll](../../../java/util/concurrent/AbstractExecutorService.html#invokeAll%28java.util.Collection, long, java.util.concurrent.TimeUnit%29), invokeAny, [invokeAny](../../../java/util/concurrent/AbstractExecutorService.html#invokeAny%28java.util.Collection, long, java.util.concurrent.TimeUnit%29)

Methods inherited from class java.lang.Object
clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, [wait](../../../java/lang/Object.html#wait%28long, int%29)

Methods inherited from interface java.util.concurrent.ExecutorService
[awaitTermination](../../../java/util/concurrent/ExecutorService.html#awaitTermination%28long, java.util.concurrent.TimeUnit%29), invokeAll, [invokeAll](../../../java/util/concurrent/ExecutorService.html#invokeAll%28java.util.Collection, long, java.util.concurrent.TimeUnit%29), invokeAny, [invokeAny](../../../java/util/concurrent/ExecutorService.html#invokeAny%28java.util.Collection, long, java.util.concurrent.TimeUnit%29), isShutdown, isTerminated

Methods inherited from interface java.util.concurrent.ExecutorService

[awaitTermination](../../../java/util/concurrent/ExecutorService.html#awaitTermination%28long, java.util.concurrent.TimeUnit%29), invokeAll, [invokeAll](../../../java/util/concurrent/ExecutorService.html#invokeAll%28java.util.Collection, long, java.util.concurrent.TimeUnit%29), invokeAny, [invokeAny](../../../java/util/concurrent/ExecutorService.html#invokeAny%28java.util.Collection, long, java.util.concurrent.TimeUnit%29), isShutdown, isTerminated

Constructor Detail

ScheduledThreadPoolExecutor

public ScheduledThreadPoolExecutor(int corePoolSize)

Creates a new ScheduledThreadPoolExecutor with the given core pool size.

Parameters:

corePoolSize - the number of threads to keep in the pool, even if they are idle.

Throws:

[IllegalArgumentException](../../../java/lang/IllegalArgumentException.html "class in java.lang") - if corePoolSize less than or equal to zero

ScheduledThreadPoolExecutor

public ScheduledThreadPoolExecutor(int corePoolSize, ThreadFactory threadFactory)

Creates a new ScheduledThreadPoolExecutor with the given initial parameters.

Parameters:

corePoolSize - the number of threads to keep in the pool, even if they are idle.

threadFactory - the factory to use when the executor creates a new thread.

Throws:

[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang") - if threadFactory is null

ScheduledThreadPoolExecutor

public ScheduledThreadPoolExecutor(int corePoolSize, RejectedExecutionHandler handler)

Creates a new ScheduledThreadPoolExecutor with the given initial parameters.

Parameters:

corePoolSize - the number of threads to keep in the pool, even if they are idle.

handler - the handler to use when execution is blocked because the thread bounds and queue capacities are reached.

Throws:

[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang") - if handler is null

ScheduledThreadPoolExecutor

public ScheduledThreadPoolExecutor(int corePoolSize, ThreadFactory threadFactory, RejectedExecutionHandler handler)

Creates a new ScheduledThreadPoolExecutor with the given initial parameters.

Parameters:

corePoolSize - the number of threads to keep in the pool, even if they are idle.

threadFactory - the factory to use when the executor creates a new thread.

handler - the handler to use when execution is blocked because the thread bounds and queue capacities are reached.

Throws:

[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang") - if threadFactory or handler is null

Method Detail

remove

public boolean remove(Runnable task)

Description copied from class: [ThreadPoolExecutor](../../../java/util/concurrent/ThreadPoolExecutor.html#remove%28java.lang.Runnable%29)

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.

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 ThreadPoolExecutor.purge() may be used to remove those Futures that have been cancelled.

Overrides:

[remove](../../../java/util/concurrent/ThreadPoolExecutor.html#remove%28java.lang.Runnable%29) in class [ThreadPoolExecutor](../../../java/util/concurrent/ThreadPoolExecutor.html "class in java.util.concurrent")

Parameters:

task - the task to remove

Returns:

true if the task was removed

schedule

public ScheduledFuture<?> schedule(Runnable command, long delay, TimeUnit unit)

Description copied from interface: [ScheduledExecutorService](../../../java/util/concurrent/ScheduledExecutorService.html#schedule%28java.lang.Runnable, long, java.util.concurrent.TimeUnit%29)

Creates and executes a one-shot action that becomes enabled after the given delay.

Specified by:

[schedule](../../../java/util/concurrent/ScheduledExecutorService.html#schedule%28java.lang.Runnable, long, java.util.concurrent.TimeUnit%29) in interface [ScheduledExecutorService](../../../java/util/concurrent/ScheduledExecutorService.html "interface in java.util.concurrent")

Parameters:

command - the task to execute.

delay - the time from now to delay execution.

unit - the time unit of the delay parameter.

Returns:

a Future representing pending completion of the task, and whose get() method will return null upon completion.

schedule

public ScheduledFuture schedule(Callable callable, long delay, TimeUnit unit)

Description copied from interface: [ScheduledExecutorService](../../../java/util/concurrent/ScheduledExecutorService.html#schedule%28java.util.concurrent.Callable, long, java.util.concurrent.TimeUnit%29)

Creates and executes a ScheduledFuture that becomes enabled after the given delay.

Specified by:

[schedule](../../../java/util/concurrent/ScheduledExecutorService.html#schedule%28java.util.concurrent.Callable, long, java.util.concurrent.TimeUnit%29) in interface [ScheduledExecutorService](../../../java/util/concurrent/ScheduledExecutorService.html "interface in java.util.concurrent")

Parameters:

callable - the function to execute.

delay - the time from now to delay execution.

unit - the time unit of the delay parameter.

Returns:

a ScheduledFuture that can be used to extract result or cancel.

scheduleAtFixedRate

public ScheduledFuture<?> scheduleAtFixedRate(Runnable command, long initialDelay, long period, TimeUnit unit)

Description copied from interface: [ScheduledExecutorService](../../../java/util/concurrent/ScheduledExecutorService.html#scheduleAtFixedRate%28java.lang.Runnable, long, long, java.util.concurrent.TimeUnit%29)

Creates and executes a periodic action that becomes enabled first after the given initial delay, and subsequently with the given period; that is executions will commence afterinitialDelay then initialDelay+period, theninitialDelay + 2 * period, and so on. If any execution of the task encounters an exception, subsequent executions are suppressed. Otherwise, the task will only terminate via cancellation or termination of the executor.

Specified by:

[scheduleAtFixedRate](../../../java/util/concurrent/ScheduledExecutorService.html#scheduleAtFixedRate%28java.lang.Runnable, long, long, java.util.concurrent.TimeUnit%29) in interface [ScheduledExecutorService](../../../java/util/concurrent/ScheduledExecutorService.html "interface in java.util.concurrent")

Parameters:

command - the task to execute.

initialDelay - the time to delay first execution.

period - the period between successive executions.

unit - the time unit of the initialDelay and period parameters

Returns:

a Future representing pending completion of the task, and whose get() method will throw an exception upon cancellation.

scheduleWithFixedDelay

public ScheduledFuture<?> scheduleWithFixedDelay(Runnable command, long initialDelay, long delay, TimeUnit unit)

Description copied from interface: [ScheduledExecutorService](../../../java/util/concurrent/ScheduledExecutorService.html#scheduleWithFixedDelay%28java.lang.Runnable, long, long, java.util.concurrent.TimeUnit%29)

Creates and executes a periodic action that becomes enabled first after the given initial delay, and subsequently with the given delay between the termination of one execution and the commencement of the next. If any execution of the task encounters an exception, subsequent executions are suppressed. Otherwise, the task will only terminate via cancellation or termination of the executor.

Specified by:

[scheduleWithFixedDelay](../../../java/util/concurrent/ScheduledExecutorService.html#scheduleWithFixedDelay%28java.lang.Runnable, long, long, java.util.concurrent.TimeUnit%29) in interface [ScheduledExecutorService](../../../java/util/concurrent/ScheduledExecutorService.html "interface in java.util.concurrent")

Parameters:

command - the task to execute.

initialDelay - the time to delay first execution.

delay - the delay between the termination of one execution and the commencement of the next.

unit - the time unit of the initialDelay and delay parameters

Returns:

a Future representing pending completion of the task, and whose get() method will throw an exception upon cancellation.

execute

public void execute(Runnable command)

Execute command with zero required delay. This has effect equivalent to schedule(command, 0, anyUnit). Note that inspections of the queue and of the list returned byshutdownNow will access the zero-delayedScheduledFuture, not the command itself.

Specified by:

[execute](../../../java/util/concurrent/Executor.html#execute%28java.lang.Runnable%29) in interface [Executor](../../../java/util/concurrent/Executor.html "interface in java.util.concurrent")

Overrides:

[execute](../../../java/util/concurrent/ThreadPoolExecutor.html#execute%28java.lang.Runnable%29) in class [ThreadPoolExecutor](../../../java/util/concurrent/ThreadPoolExecutor.html "class in java.util.concurrent")

Parameters:

command - the task to execute

Throws:

[RejectedExecutionException](../../../java/util/concurrent/RejectedExecutionException.html "class in java.util.concurrent") - at discretion ofRejectedExecutionHandler, if task cannot be accepted for execution because the executor has been shut down.

[NullPointerException](../../../java/lang/NullPointerException.html "class in java.lang") - if command is null

submit

public Future<?> submit(Runnable task)

Description copied from interface: [ExecutorService](../../../java/util/concurrent/ExecutorService.html#submit%28java.lang.Runnable%29)

Submits a Runnable task for execution and returns a Future representing that task.

Specified by:

[submit](../../../java/util/concurrent/ExecutorService.html#submit%28java.lang.Runnable%29) in interface [ExecutorService](../../../java/util/concurrent/ExecutorService.html "interface in java.util.concurrent")

Overrides:

[submit](../../../java/util/concurrent/AbstractExecutorService.html#submit%28java.lang.Runnable%29) in class [AbstractExecutorService](../../../java/util/concurrent/AbstractExecutorService.html "class in java.util.concurrent")

Parameters:

task - the task to submit

Returns:

a Future representing pending completion of the task, and whose get() method will return null upon completion.

submit

public Future submit(Runnable task, T result)

Description copied from interface: [ExecutorService](../../../java/util/concurrent/ExecutorService.html#submit%28java.lang.Runnable, T%29)

Submits a Runnable task for execution and returns a Future representing that task that will upon completion return the given result

Specified by:

[submit](../../../java/util/concurrent/ExecutorService.html#submit%28java.lang.Runnable, T%29) in interface [ExecutorService](../../../java/util/concurrent/ExecutorService.html "interface in java.util.concurrent")

Overrides:

[submit](../../../java/util/concurrent/AbstractExecutorService.html#submit%28java.lang.Runnable, T%29) in class [AbstractExecutorService](../../../java/util/concurrent/AbstractExecutorService.html "class in java.util.concurrent")

Parameters:

task - the task to submit

result - the result to return

Returns:

a Future representing pending completion of the task, and whose get() method will return the given result upon completion.

submit

public Future submit(Callable task)

Description copied from interface: [ExecutorService](../../../java/util/concurrent/ExecutorService.html#submit%28java.util.concurrent.Callable%29)

Submits a value-returning task for execution and returns a Future representing the pending results of the task.

If you would like to immediately block waiting for a task, you can use constructions of the formresult = exec.submit(aCallable).get();

Note: The Executors class includes a set of methods that can convert some other common closure-like objects, for example, PrivilegedAction toCallable form so they can be submitted.

Specified by:

[submit](../../../java/util/concurrent/ExecutorService.html#submit%28java.util.concurrent.Callable%29) in interface [ExecutorService](../../../java/util/concurrent/ExecutorService.html "interface in java.util.concurrent")

Overrides:

[submit](../../../java/util/concurrent/AbstractExecutorService.html#submit%28java.util.concurrent.Callable%29) in class [AbstractExecutorService](../../../java/util/concurrent/AbstractExecutorService.html "class in java.util.concurrent")

Parameters:

task - the task to submit

Returns:

a Future representing pending completion of the task

setContinueExistingPeriodicTasksAfterShutdownPolicy

public void setContinueExistingPeriodicTasksAfterShutdownPolicy(boolean value)

Set policy on whether to continue executing existing periodic tasks even when this executor has been shutdown. In this case, these tasks will only terminate uponshutdownNow, or after setting the policy tofalse when already shutdown. This value is by default false.

Parameters:

value - if true, continue after shutdown, else don't.

getContinueExistingPeriodicTasksAfterShutdownPolicy

public boolean getContinueExistingPeriodicTasksAfterShutdownPolicy()

Get the policy on whether to continue executing existing periodic tasks even when this executor has beenshutdown. In this case, these tasks will only terminate upon shutdownNow or after setting the policy to false when already shutdown. This value is by default false.

Returns:

true if will continue after shutdown.

setExecuteExistingDelayedTasksAfterShutdownPolicy

public void setExecuteExistingDelayedTasksAfterShutdownPolicy(boolean value)

Set policy on whether to execute existing delayed tasks even when this executor has been shutdown. In this case, these tasks will only terminate uponshutdownNow, or after setting the policy tofalse when already shutdown. This value is by default true.

Parameters:

value - if true, execute after shutdown, else don't.

getExecuteExistingDelayedTasksAfterShutdownPolicy

public boolean getExecuteExistingDelayedTasksAfterShutdownPolicy()

Get policy on whether to execute existing delayed tasks even when this executor has been shutdown. In this case, these tasks will only terminate uponshutdownNow, or after setting the policy tofalse when already shutdown. This value is by default true.

Returns:

true if will execute after shutdown.

shutdown

public void shutdown()

Initiates an orderly shutdown in which previously submitted tasks are executed, but no new tasks will be accepted. If theExecuteExistingDelayedTasksAfterShutdownPolicy has been set false, existing delayed tasks whose delays have not yet elapsed are cancelled. And unless theContinueExistingPeriodicTasksAfterShutdownPolicy has been set true, future executions of existing periodic tasks will be cancelled.

Specified by:

[shutdown](../../../java/util/concurrent/ExecutorService.html#shutdown%28%29) in interface [ExecutorService](../../../java/util/concurrent/ExecutorService.html "interface in java.util.concurrent")

Overrides:

[shutdown](../../../java/util/concurrent/ThreadPoolExecutor.html#shutdown%28%29) in class [ThreadPoolExecutor](../../../java/util/concurrent/ThreadPoolExecutor.html "class in java.util.concurrent")

shutdownNow

public 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.

There are no guarantees beyond best-effort attempts to stop processing actively executing tasks. This implementation cancels tasks via Thread.interrupt(), so if any tasks mask or fail to respond to interrupts, they may never terminate.

Specified by:

[shutdownNow](../../../java/util/concurrent/ExecutorService.html#shutdownNow%28%29) in interface [ExecutorService](../../../java/util/concurrent/ExecutorService.html "interface in java.util.concurrent")

Overrides:

[shutdownNow](../../../java/util/concurrent/ThreadPoolExecutor.html#shutdownNow%28%29) in class [ThreadPoolExecutor](../../../java/util/concurrent/ThreadPoolExecutor.html "class in java.util.concurrent")

Returns:

list of tasks that never commenced execution. Each element of this list is a ScheduledFuture, including those tasks submitted using execute, which are for scheduling purposes used as the basis of a zero-delayScheduledFuture.

getQueue

public BlockingQueue<Runnable> getQueue()

Returns the task queue used by this executor. Each element of this queue is a ScheduledFuture, including those tasks submitted using execute which are for scheduling purposes used as the basis of a zero-delayScheduledFuture. Iteration over this queue is_not_ guaranteed to traverse tasks in the order in which they will execute.

Overrides:

[getQueue](../../../java/util/concurrent/ThreadPoolExecutor.html#getQueue%28%29) in class [ThreadPoolExecutor](../../../java/util/concurrent/ThreadPoolExecutor.html "class in java.util.concurrent")

Returns:

the task queue

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For further API reference and developer documentation, see Java 2 SDK SE Developer Documentation. That documentation contains more detailed, developer-targeted descriptions, with conceptual overviews, definitions of terms, workarounds, and working code examples.