public class Executors extends Object
Executor, ExecutorService, ScheduledExecutorService, ThreadFactory, and Callable classes defined in this
 package. This class supports the following kinds of methods:
 ExecutorService
        set up with commonly useful configuration settings.
   ScheduledExecutorService
        set up with commonly useful configuration settings.
   ThreadFactory
        that sets newly created threads to a known state.
   Callable
        out of other closure-like forms, so they can be used
        in execution methods requiring Callable.
 | Modifier and Type | Method and Description | 
|---|---|
| static Callable<Object> | callable(PrivilegedAction<?> action)Returns a  Callableobject that, when
 called, runs the given privileged action and returns its result. | 
| static Callable<Object> | callable(PrivilegedExceptionAction<?> action)Returns a  Callableobject that, when
 called, runs the given privileged exception action and returns
 its result. | 
| static Callable<Object> | callable(Runnable task)Returns a  Callableobject that, when
 called, runs the given task and returnsnull. | 
| static <T> Callable<T> | callable(Runnable task,
        T result)Returns a  Callableobject that, when
 called, runs the given task and returns the given result. | 
| static ThreadFactory | defaultThreadFactory()Returns a default thread factory used to create new threads. | 
| static ExecutorService | newCachedThreadPool()Creates a thread pool that creates new threads as needed, but
 will reuse previously constructed threads when they are
 available. | 
| static ExecutorService | newCachedThreadPool(ThreadFactory threadFactory)Creates a thread pool that creates new threads as needed, but
 will reuse previously constructed threads when they are
 available, and uses the provided
 ThreadFactory to create new threads when needed. | 
| static ExecutorService | newFixedThreadPool(int nThreads)Creates a thread pool that reuses a fixed number of threads
 operating off a shared unbounded queue. | 
| static ExecutorService | newFixedThreadPool(int nThreads,
                  ThreadFactory threadFactory)Creates a thread pool that reuses a fixed number of threads
 operating off a shared unbounded queue, using the provided
 ThreadFactory to create new threads when needed. | 
| static ScheduledExecutorService | newScheduledThreadPool(int corePoolSize)Creates a thread pool that can schedule commands to run after a
 given delay, or to execute periodically. | 
| static ScheduledExecutorService | newScheduledThreadPool(int corePoolSize,
                      ThreadFactory threadFactory)Creates a thread pool that can schedule commands to run after a
 given delay, or to execute periodically. | 
| static ExecutorService | newSingleThreadExecutor()Creates an Executor that uses a single worker thread operating
 off an unbounded queue. | 
| static ExecutorService | newSingleThreadExecutor(ThreadFactory threadFactory)Creates an Executor that uses a single worker thread operating
 off an unbounded queue, and uses the provided ThreadFactory to
 create a new thread when needed. | 
| static ScheduledExecutorService | newSingleThreadScheduledExecutor()Creates a single-threaded executor that can schedule commands
 to run after a given delay, or to execute periodically. | 
| static ScheduledExecutorService | newSingleThreadScheduledExecutor(ThreadFactory threadFactory)Creates a single-threaded executor that can schedule commands
 to run after a given delay, or to execute periodically. | 
| static ExecutorService | newWorkStealingPool()Creates a work-stealing thread pool using all
  available processorsas its target parallelism level. | 
| static ExecutorService | newWorkStealingPool(int parallelism)Creates a thread pool that maintains enough threads to support
 the given parallelism level, and may use multiple queues to
 reduce contention. | 
| static <T> Callable<T> | privilegedCallable(Callable<T> callable)Returns a  Callableobject that will, when called,
 execute the givencallableunder the current access
 control context. | 
| static <T> Callable<T> | privilegedCallableUsingCurrentClassLoader(Callable<T> callable)Returns a  Callableobject that will, when called,
 execute the givencallableunder the current access
 control context, with the current context class loader as the
 context class loader. | 
| static ThreadFactory | privilegedThreadFactory()Returns a thread factory used to create new threads that
 have the same permissions as the current thread. | 
| static ExecutorService | unconfigurableExecutorService(ExecutorService executor)Returns an object that delegates all defined  ExecutorServicemethods to the given executor, but not any
 other methods that might otherwise be accessible using
 casts. | 
| static ScheduledExecutorService | unconfigurableScheduledExecutorService(ScheduledExecutorService executor)Returns an object that delegates all defined  ScheduledExecutorServicemethods to the given executor, but
 not any other methods that might otherwise be accessible using
 casts. | 
public static ExecutorService newFixedThreadPool(int nThreads)
nThreads threads will be active processing tasks.
 If additional tasks are submitted when all threads are active,
 they will wait in the queue until a thread is available.
 If any thread terminates due to a failure during execution
 prior to shutdown, a new one will take its place if needed to
 execute subsequent tasks.  The threads in the pool will exist
 until it is explicitly shutdown.nThreads - the number of threads in the poolIllegalArgumentException - if nThreads <= 0public static ExecutorService newWorkStealingPool(int parallelism)
parallelism - the targeted parallelism levelIllegalArgumentException - if parallelism <= 0public static ExecutorService newWorkStealingPool()
available processors
 as its target parallelism level.newWorkStealingPool(int)public static ExecutorService newFixedThreadPool(int nThreads, ThreadFactory threadFactory)
nThreads threads will be active processing
 tasks.  If additional tasks are submitted when all threads are
 active, they will wait in the queue until a thread is
 available.  If any thread terminates due to a failure during
 execution prior to shutdown, a new one will take its place if
 needed to execute subsequent tasks.  The threads in the pool will
 exist until it is explicitly shutdown.nThreads - the number of threads in the poolthreadFactory - the factory to use when creating new threadsNullPointerException - if threadFactory is nullIllegalArgumentException - if nThreads <= 0public static ExecutorService newSingleThreadExecutor()
newFixedThreadPool(1) the returned executor is
 guaranteed not to be reconfigurable to use additional threads.public static ExecutorService newSingleThreadExecutor(ThreadFactory threadFactory)
newFixedThreadPool(1, threadFactory) the
 returned executor is guaranteed not to be reconfigurable to use
 additional threads.threadFactory - the factory to use when creating new
 threadsNullPointerException - if threadFactory is nullpublic static ExecutorService newCachedThreadPool()
execute will reuse previously constructed
 threads if available. If no existing thread is available, a new
 thread will be created and added to the pool. Threads that have
 not been used for sixty seconds are terminated and removed from
 the cache. Thus, a pool that remains idle for long enough will
 not consume any resources. Note that pools with similar
 properties but different details (for example, timeout parameters)
 may be created using ThreadPoolExecutor constructors.public static ExecutorService newCachedThreadPool(ThreadFactory threadFactory)
threadFactory - the factory to use when creating new threadsNullPointerException - if threadFactory is nullpublic static ScheduledExecutorService newSingleThreadScheduledExecutor()
newScheduledThreadPool(1) the returned executor is
 guaranteed not to be reconfigurable to use additional threads.public static ScheduledExecutorService newSingleThreadScheduledExecutor(ThreadFactory threadFactory)
newScheduledThreadPool(1, threadFactory)
 the returned executor is guaranteed not to be reconfigurable to
 use additional threads.threadFactory - the factory to use when creating new
 threadsNullPointerException - if threadFactory is nullpublic static ScheduledExecutorService newScheduledThreadPool(int corePoolSize)
corePoolSize - the number of threads to keep in the pool,
 even if they are idleIllegalArgumentException - if corePoolSize < 0public static ScheduledExecutorService newScheduledThreadPool(int corePoolSize, ThreadFactory threadFactory)
corePoolSize - the number of threads to keep in the pool,
 even if they are idlethreadFactory - the factory to use when the executor
 creates a new threadIllegalArgumentException - if corePoolSize < 0NullPointerException - if threadFactory is nullpublic static ExecutorService unconfigurableExecutorService(ExecutorService executor)
ExecutorService methods to the given executor, but not any
 other methods that might otherwise be accessible using
 casts. This provides a way to safely "freeze" configuration and
 disallow tuning of a given concrete implementation.executor - the underlying implementationExecutorService instanceNullPointerException - if executor nullpublic static ScheduledExecutorService unconfigurableScheduledExecutorService(ScheduledExecutorService executor)
ScheduledExecutorService methods to the given executor, but
 not any other methods that might otherwise be accessible using
 casts. This provides a way to safely "freeze" configuration and
 disallow tuning of a given concrete implementation.executor - the underlying implementationScheduledExecutorService instanceNullPointerException - if executor nullpublic static ThreadFactory defaultThreadFactory()
ThreadGroup. If there is a SecurityManager, it uses the group of System.getSecurityManager(), else the group of the thread
 invoking this defaultThreadFactory method. Each new
 thread is created as a non-daemon thread with priority set to
 the smaller of Thread.NORM_PRIORITY and the maximum
 priority permitted in the thread group.  New threads have names
 accessible via Thread.getName() of
 pool-N-thread-M, where N is the sequence
 number of this factory, and M is the sequence number
 of the thread created by this factory.public static ThreadFactory privilegedThreadFactory()
defaultThreadFactory(), additionally setting the
 AccessControlContext and contextClassLoader of new threads to
 be the same as the thread invoking this
 privilegedThreadFactory method.  A new
 privilegedThreadFactory can be created within an
 AccessController.doPrivileged
 action setting the current thread's access control context to
 create threads with the selected permission settings holding
 within that action.
 Note that while tasks running within such threads will have
 the same access control and class loader settings as the
 current thread, they need not have the same ThreadLocal or InheritableThreadLocal values. If necessary,
 particular values of thread locals can be set or reset before
 any task runs in ThreadPoolExecutor subclasses using
 ThreadPoolExecutor.beforeExecute(Thread, Runnable).
 Also, if it is necessary to initialize worker threads to have
 the same InheritableThreadLocal settings as some other
 designated thread, you can create a custom ThreadFactory in
 which that thread waits for and services requests to create
 others that will inherit its values.
AccessControlException - if the current access control
 context does not have permission to both get and set context
 class loaderpublic static <T> Callable<T> callable(Runnable task, T result)
Callable object that, when
 called, runs the given task and returns the given result.  This
 can be useful when applying methods requiring a
 Callable to an otherwise resultless action.T - the type of the resulttask - the task to runresult - the result to returnNullPointerException - if task nullpublic static Callable<Object> callable(Runnable task)
Callable object that, when
 called, runs the given task and returns null.task - the task to runNullPointerException - if task nullpublic static Callable<Object> callable(PrivilegedAction<?> action)
Callable object that, when
 called, runs the given privileged action and returns its result.action - the privileged action to runNullPointerException - if action nullpublic static Callable<Object> callable(PrivilegedExceptionAction<?> action)
Callable object that, when
 called, runs the given privileged exception action and returns
 its result.action - the privileged exception action to runNullPointerException - if action nullpublic static <T> Callable<T> privilegedCallable(Callable<T> callable)
Callable object that will, when called,
 execute the given callable under the current access
 control context. This method should normally be invoked within
 an AccessController.doPrivileged
 action to create callables that will, if possible, execute
 under the selected permission settings holding within that
 action; or if not possible, throw an associated AccessControlException.T - the type of the callable's resultcallable - the underlying taskNullPointerException - if callable nullpublic static <T> Callable<T> privilegedCallableUsingCurrentClassLoader(Callable<T> callable)
Callable object that will, when called,
 execute the given callable under the current access
 control context, with the current context class loader as the
 context class loader. This method should normally be invoked
 within an
 AccessController.doPrivileged
 action to create callables that will, if possible, execute
 under the selected permission settings holding within that
 action; or if not possible, throw an associated AccessControlException.T - the type of the callable's resultcallable - the underlying taskNullPointerException - if callable nullAccessControlException - if the current access control
 context does not have permission to both set and get context
 class loader 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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