Added in API level 24

Summary: Nested Classes | Ctors | Methods | Inherited Methods

CompletableFuture

public class CompletableFuture
extends Object implements CompletionStage, Future

java.lang.Object
↳	java.util.concurrent.CompletableFuture

A Future that may be explicitly completed (setting its value and status), and may be used as a CompletionStage, supporting dependent functions and actions that trigger upon its completion.

When two or more threads attempt to complete, completeExceptionally, or cancel a CompletableFuture, only one of them succeeds.

In addition to these and related methods for directly manipulating status and results, CompletableFuture implements interface CompletionStage with the following policies:

Actions supplied for dependent completions of non-async methods may be performed by the thread that completes the current CompletableFuture, or by any other caller of a completion method.
All async methods without an explicit Executor argument are performed using the ForkJoinPool.commonPool() (unless it does not support a parallelism level of at least two, in which case, a new Thread is created to run each task). To simplify monitoring, debugging, and tracking, all generated asynchronous tasks are instances of the marker interface AsynchronousCompletionTask. Operations with time-delays can use adapter methods defined in this class, for example: supplyAsync(supplier, delayedExecutor(timeout, timeUnit)). To support methods with delays and timeouts, this class maintains at most one daemon thread for triggering and cancelling actions, not for running them.
All CompletionStage methods are implemented independently of other public methods, so the behavior of one method is not impacted by overrides of others in subclasses.

CompletableFuture also implements Future with the following policies:

Since (unlike FutureTask) this class has no direct control over the computation that causes it to be completed, cancellation is treated as just another form of exceptional completion. Method cancel has the same effect as completeExceptionally(new CancellationException()). Method isCompletedExceptionally() can be used to determine if a CompletableFuture completed in any exceptional fashion.
In case of exceptional completion with a CompletionException, methods get() and get(long, java.util.concurrent.TimeUnit) throw an ExecutionException with the same cause as held in the corresponding CompletionException. To simplify usage in most contexts, this class also defines methods join() and getNow(T) that instead throw the CompletionException directly in these cases.

Arguments used to pass a completion result (that is, for parameters of type T) for methods accepting them may be null, but passing a null value for any other parameter will result in a NullPointerException being thrown.

Summary

Nested classes
`interface`	`CompletableFuture.AsynchronousCompletionTask` A marker interface identifying asynchronous tasks produced by `async` methods.

Public constructors
`CompletableFuture()` Creates a new incomplete CompletableFuture.

Public methods
`CompletableFuture<Void>`	`acceptEither(CompletionStage other, Consumer action)` Returns a new CompletionStage that, when either this or the other given stage complete normally, is executed with the corresponding result as argument to the supplied action.
`CompletableFuture<Void>`	`acceptEitherAsync(CompletionStage other, Consumer action)` Returns a new CompletionStage that, when either this or the other given stage complete normally, is executed using this stage's default asynchronous execution facility, with the corresponding result as argument to the supplied action.
`CompletableFuture<Void>`	`acceptEitherAsync(CompletionStage other, Consumer action, Executor executor)` Returns a new CompletionStage that, when either this or the other given stage complete normally, is executed using the supplied executor, with the corresponding result as argument to the supplied action.
`static CompletableFuture<Void>`	`allOf(CompletableFuture... cfs)` Returns a new CompletableFuture that is completed when all of the given CompletableFutures complete.
`static CompletableFuture<Object>`	`anyOf(CompletableFuture... cfs)` Returns a new CompletableFuture that is completed when any of the given CompletableFutures complete, with the same result.
`CompletableFuture`	`applyToEither(CompletionStage other, Function fn)` Returns a new CompletionStage that, when either this or the other given stage complete normally, is executed with the corresponding result as argument to the supplied function.
`CompletableFuture`	`applyToEitherAsync(CompletionStage other, Function fn, Executor executor)` Returns a new CompletionStage that, when either this or the other given stage complete normally, is executed using the supplied executor, with the corresponding result as argument to the supplied function.
`CompletableFuture`	`applyToEitherAsync(CompletionStage other, Function fn)` Returns a new CompletionStage that, when either this or the other given stage complete normally, is executed using this stage's default asynchronous execution facility, with the corresponding result as argument to the supplied function.
`boolean`	`cancel(boolean mayInterruptIfRunning)` If not already completed, completes this CompletableFuture with a `CancellationException`.
`boolean`	`complete(T value)` If not already completed, sets the value returned by `get()` and related methods to the given value.
`CompletableFuture`	`completeAsync(Supplier supplier, Executor executor)` Completes this CompletableFuture with the result of the given Supplier function invoked from an asynchronous task using the given executor.
`CompletableFuture`	`completeAsync(Supplier supplier)` Completes this CompletableFuture with the result of the given Supplier function invoked from an asynchronous task using the default executor.
`boolean`	`completeExceptionally(Throwable ex)` If not already completed, causes invocations of `get()` and related methods to throw the given exception.
`CompletableFuture`	`completeOnTimeout(T value, long timeout, TimeUnit unit)` Completes this CompletableFuture with the given value if not otherwise completed before the given timeout.
`static CompletableFuture`	`completedFuture(U value)` Returns a new CompletableFuture that is already completed with the given value.
`static CompletionStage`	`completedStage(U value)` Returns a new CompletionStage that is already completed with the given value and supports only those methods in interface `CompletionStage`.
`CompletableFuture`	`copy()` Returns a new CompletableFuture that is completed normally with the same value as this CompletableFuture when it completes normally.
`Executor`	`defaultExecutor()` Returns the default Executor used for async methods that do not specify an Executor.
`static Executor`	`delayedExecutor(long delay, TimeUnit unit, Executor executor)` Returns a new Executor that submits a task to the given base executor after the given delay (or no delay if non-positive).
`static Executor`	`delayedExecutor(long delay, TimeUnit unit)` Returns a new Executor that submits a task to the default executor after the given delay (or no delay if non-positive).
`Throwable`	`exceptionNow()` Returns the exception thrown by the task, without waiting.
`CompletableFuture`	`exceptionally(Function<Throwable, ? extends T> fn)` Returns a new CompletionStage that, when this stage completes exceptionally, is executed with this stage's exception as the argument to the supplied function.
`CompletableFuture`	`exceptionallyAsync(Function<Throwable, ? extends T> fn)` Returns a new CompletionStage that, when this stage completes exceptionally, is executed with this stage's exception as the argument to the supplied function, using this stage's default asynchronous execution facility.
`CompletableFuture`	`exceptionallyAsync(Function<Throwable, ? extends T> fn, Executor executor)` Returns a new CompletionStage that, when this stage completes exceptionally, is executed with this stage's exception as the argument to the supplied function, using the supplied Executor.
`CompletableFuture`	`exceptionallyCompose(Function<Throwable, ? extends CompletionStage> fn)` Returns a new CompletionStage that, when this stage completes exceptionally, is composed using the results of the supplied function applied to this stage's exception.
`CompletableFuture`	`exceptionallyComposeAsync(Function<Throwable, ? extends CompletionStage> fn, Executor executor)` Returns a new CompletionStage that, when this stage completes exceptionally, is composed using the results of the supplied function applied to this stage's exception, using the supplied Executor.
`CompletableFuture`	`exceptionallyComposeAsync(Function<Throwable, ? extends CompletionStage> fn)` Returns a new CompletionStage that, when this stage completes exceptionally, is composed using the results of the supplied function applied to this stage's exception, using this stage's default asynchronous execution facility.
`static CompletableFuture`	`failedFuture(Throwable ex)` Returns a new CompletableFuture that is already completed exceptionally with the given exception.
`static CompletionStage`	`failedStage(Throwable ex)` Returns a new CompletionStage that is already completed exceptionally with the given exception and supports only those methods in interface `CompletionStage`.
`T`	`get(long timeout, TimeUnit unit)` Waits if necessary for at most the given time for this future to complete, and then returns its result, if available.
`T`	`get()` Waits if necessary for this future to complete, and then returns its result.
`T`	`getNow(T valueIfAbsent)` Returns the result value (or throws any encountered exception) if completed, else returns the given valueIfAbsent.
`int`	`getNumberOfDependents()` Returns the estimated number of CompletableFutures whose completions are awaiting completion of this CompletableFuture.
`CompletableFuture`	`handle(BiFunctionThrowable, ? extends U> fn)` Returns a new CompletionStage that, when this stage completes either normally or exceptionally, is executed with this stage's result and exception as arguments to the supplied function.
`CompletableFuture`	`handleAsync(BiFunctionThrowable, ? extends U> fn)` Returns a new CompletionStage that, when this stage completes either normally or exceptionally, is executed using this stage's default asynchronous execution facility, with this stage's result and exception as arguments to the supplied function.
`CompletableFuture`	`handleAsync(BiFunctionThrowable, ? extends U> fn, Executor executor)` Returns a new CompletionStage that, when this stage completes either normally or exceptionally, is executed using the supplied executor, with this stage's result and exception as arguments to the supplied function.
`boolean`	`isCancelled()` Returns `true` if this CompletableFuture was cancelled before it completed normally.
`boolean`	`isCompletedExceptionally()` Returns `true` if this CompletableFuture completed exceptionally, in any way.
`boolean`	`isDone()` Returns `true` if completed in any fashion: normally, exceptionally, or via cancellation.
`T`	`join()` Returns the result value when complete, or throws an (unchecked) exception if completed exceptionally.
`CompletionStage`	`minimalCompletionStage()` Returns a new CompletionStage that is completed normally with the same value as this CompletableFuture when it completes normally, and cannot be independently completed or otherwise used in ways not defined by the methods of interface `CompletionStage`.
`CompletableFuture`	`newIncompleteFuture()` Returns a new incomplete CompletableFuture of the type to be returned by a CompletionStage method.
`void`	`obtrudeException(Throwable ex)` Forcibly causes subsequent invocations of method `get()` and related methods to throw the given exception, whether or not already completed.
`void`	`obtrudeValue(T value)` Forcibly sets or resets the value subsequently returned by method `get()` and related methods, whether or not already completed.
`CompletableFuture`	`orTimeout(long timeout, TimeUnit unit)` Exceptionally completes this CompletableFuture with a `TimeoutException` if not otherwise completed before the given timeout.
`T`	`resultNow()` Returns the computed result, without waiting.
`CompletableFuture<Void>`	`runAfterBoth(CompletionStage other, Runnable action)` Returns a new CompletionStage that, when this and the other given stage both complete normally, executes the given action.
`CompletableFuture<Void>`	`runAfterBothAsync(CompletionStage other, Runnable action)` Returns a new CompletionStage that, when this and the other given stage both complete normally, executes the given action using this stage's default asynchronous execution facility.
`CompletableFuture<Void>`	`runAfterBothAsync(CompletionStage other, Runnable action, Executor executor)` Returns a new CompletionStage that, when this and the other given stage both complete normally, executes the given action using the supplied executor.
`CompletableFuture<Void>`	`runAfterEither(CompletionStage other, Runnable action)` Returns a new CompletionStage that, when either this or the other given stage complete normally, executes the given action.
`CompletableFuture<Void>`	`runAfterEitherAsync(CompletionStage other, Runnable action, Executor executor)` Returns a new CompletionStage that, when either this or the other given stage complete normally, executes the given action using the supplied executor.
`CompletableFuture<Void>`	`runAfterEitherAsync(CompletionStage other, Runnable action)` Returns a new CompletionStage that, when either this or the other given stage complete normally, executes the given action using this stage's default asynchronous execution facility.
`static CompletableFuture<Void>`	`runAsync(Runnable runnable)` Returns a new CompletableFuture that is asynchronously completed by a task running in the `ForkJoinPool.commonPool()` after it runs the given action.
`static CompletableFuture<Void>`	`runAsync(Runnable runnable, Executor executor)` Returns a new CompletableFuture that is asynchronously completed by a task running in the given executor after it runs the given action.
`Future.State`	`state()`
`static CompletableFuture`	`supplyAsync(Supplier supplier)` Returns a new CompletableFuture that is asynchronously completed by a task running in the `ForkJoinPool.commonPool()` with the value obtained by calling the given Supplier.
`static CompletableFuture`	`supplyAsync(Supplier supplier, Executor executor)` Returns a new CompletableFuture that is asynchronously completed by a task running in the given executor with the value obtained by calling the given Supplier.
`CompletableFuture<Void>`	`thenAccept(Consumer action)` Returns a new CompletionStage that, when this stage completes normally, is executed with this stage's result as the argument to the supplied action.
`CompletableFuture<Void>`	`thenAcceptAsync(Consumer action, Executor executor)` Returns a new CompletionStage that, when this stage completes normally, is executed using the supplied Executor, with this stage's result as the argument to the supplied action.
`CompletableFuture<Void>`	`thenAcceptAsync(Consumer action)` Returns a new CompletionStage that, when this stage completes normally, is executed using this stage's default asynchronous execution facility, with this stage's result as the argument to the supplied action.
`CompletableFuture<Void>`	`thenAcceptBoth(CompletionStage other, BiConsumer action)` Returns a new CompletionStage that, when this and the other given stage both complete normally, is executed with the two results as arguments to the supplied action.
`CompletableFuture<Void>`	`thenAcceptBothAsync(CompletionStage other, BiConsumer action, Executor executor)` Returns a new CompletionStage that, when this and the other given stage both complete normally, is executed using the supplied executor, with the two results as arguments to the supplied action.
`CompletableFuture<Void>`	`thenAcceptBothAsync(CompletionStage other, BiConsumer action)` Returns a new CompletionStage that, when this and the other given stage both complete normally, is executed using this stage's default asynchronous execution facility, with the two results as arguments to the supplied action.
`CompletableFuture`	`thenApply(Function fn)` Returns a new CompletionStage that, when this stage completes normally, is executed with this stage's result as the argument to the supplied function.
`CompletableFuture`	`thenApplyAsync(Function fn, Executor executor)` Returns a new CompletionStage that, when this stage completes normally, is executed using the supplied Executor, with this stage's result as the argument to the supplied function.
`CompletableFuture`	`thenApplyAsync(Function fn)` Returns a new CompletionStage that, when this stage completes normally, is executed using this stage's default asynchronous execution facility, with this stage's result as the argument to the supplied function.
`CompletableFuture`	`thenCombine(CompletionStage other, BiFunction fn)` Returns a new CompletionStage that, when this and the other given stage both complete normally, is executed with the two results as arguments to the supplied function.
`CompletableFuture`	`thenCombineAsync(CompletionStage other, BiFunction fn, Executor executor)` Returns a new CompletionStage that, when this and the other given stage both complete normally, is executed using the supplied executor, with the two results as arguments to the supplied function.
`CompletableFuture`	`thenCombineAsync(CompletionStage other, BiFunction fn)` Returns a new CompletionStage that, when this and the other given stage both complete normally, is executed using this stage's default asynchronous execution facility, with the two results as arguments to the supplied function.
`CompletableFuture`	`thenCompose(FunctionCompletionStage> fn)` Returns a new CompletionStage that is completed with the same value as the CompletionStage returned by the given function.
`CompletableFuture`	`thenComposeAsync(FunctionCompletionStage> fn)` Returns a new CompletionStage that is completed with the same value as the CompletionStage returned by the given function, executed using this stage's default asynchronous execution facility.
`CompletableFuture`	`thenComposeAsync(FunctionCompletionStage> fn, Executor executor)` Returns a new CompletionStage that is completed with the same value as the CompletionStage returned by the given function, executed using the supplied Executor.
`CompletableFuture<Void>`	`thenRun(Runnable action)` Returns a new CompletionStage that, when this stage completes normally, executes the given action.
`CompletableFuture<Void>`	`thenRunAsync(Runnable action, Executor executor)` Returns a new CompletionStage that, when this stage completes normally, executes the given action using the supplied Executor.
`CompletableFuture<Void>`	`thenRunAsync(Runnable action)` Returns a new CompletionStage that, when this stage completes normally, executes the given action using this stage's default asynchronous execution facility.
`CompletableFuture`	`toCompletableFuture()` Returns this CompletableFuture.
`String`	`toString()` Returns a string identifying this CompletableFuture, as well as its completion state.
`CompletableFuture`	`whenComplete(BiConsumerThrowable> action)` Returns a new CompletionStage with the same result or exception as this stage, that executes the given action when this stage completes.
`CompletableFuture`	`whenCompleteAsync(BiConsumerThrowable> action, Executor executor)` Returns a new CompletionStage with the same result or exception as this stage, that executes the given action using the supplied Executor when this stage completes.
`CompletableFuture`	`whenCompleteAsync(BiConsumerThrowable> action)` Returns a new CompletionStage with the same result or exception as this stage, that executes the given action using this stage's default asynchronous execution facility when this stage completes.

Inherited methods

From class


        
          java.lang.Object

`Object`	`clone()` Creates and returns a copy of this object.
`boolean`	`equals(Object obj)` Indicates whether some other object is "equal to" this one.
`void`	`finalize()` Called by the garbage collector on an object when garbage collection determines that there are no more references to the object.
`final Class`	`getClass()` Returns the runtime class of this `Object`.
`int`	`hashCode()` Returns a hash code value for the object.
`final void`	`notify()` Wakes up a single thread that is waiting on this object's monitor.
`final void`	`notifyAll()` Wakes up all threads that are waiting on this object's monitor.
`String`	`toString()` Returns a string representation of the object.
`final void`	`wait(long timeoutMillis, int nanos)` Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait(long timeoutMillis)` Causes the current thread to wait until it is awakened, typically by being notified or interrupted, or until a certain amount of real time has elapsed.
`final void`	`wait()` Causes the current thread to wait until it is awakened, typically by being notified or interrupted.

From interface


        
          java.util.concurrent.CompletionStage

`abstract CompletionStage<Void>`	`acceptEither(CompletionStage other, Consumer action)` Returns a new CompletionStage that, when either this or the other given stage complete normally, is executed with the corresponding result as argument to the supplied action.
`abstract CompletionStage<Void>`	`acceptEitherAsync(CompletionStage other, Consumer action, Executor executor)` Returns a new CompletionStage that, when either this or the other given stage complete normally, is executed using the supplied executor, with the corresponding result as argument to the supplied action.
`abstract CompletionStage<Void>`	`acceptEitherAsync(CompletionStage other, Consumer action)` Returns a new CompletionStage that, when either this or the other given stage complete normally, is executed using this stage's default asynchronous execution facility, with the corresponding result as argument to the supplied action.
`abstract CompletionStage`	`applyToEither(CompletionStage other, Function fn)` Returns a new CompletionStage that, when either this or the other given stage complete normally, is executed with the corresponding result as argument to the supplied function.
`abstract CompletionStage`	`applyToEitherAsync(CompletionStage other, Function fn, Executor executor)` Returns a new CompletionStage that, when either this or the other given stage complete normally, is executed using the supplied executor, with the corresponding result as argument to the supplied function.
`abstract CompletionStage`	`applyToEitherAsync(CompletionStage other, Function fn)` Returns a new CompletionStage that, when either this or the other given stage complete normally, is executed using this stage's default asynchronous execution facility, with the corresponding result as argument to the supplied function.
`abstract CompletionStage`	`exceptionally(Function<Throwable, ? extends T> fn)` Returns a new CompletionStage that, when this stage completes exceptionally, is executed with this stage's exception as the argument to the supplied function.
`default CompletionStage`	`exceptionallyAsync(Function<Throwable, ? extends T> fn)` Returns a new CompletionStage that, when this stage completes exceptionally, is executed with this stage's exception as the argument to the supplied function, using this stage's default asynchronous execution facility.
`default CompletionStage`	`exceptionallyAsync(Function<Throwable, ? extends T> fn, Executor executor)` Returns a new CompletionStage that, when this stage completes exceptionally, is executed with this stage's exception as the argument to the supplied function, using the supplied Executor.
`default CompletionStage`	`exceptionallyCompose(Function<Throwable, ? extends CompletionStage> fn)` Returns a new CompletionStage that, when this stage completes exceptionally, is composed using the results of the supplied function applied to this stage's exception.
`default CompletionStage`	`exceptionallyComposeAsync(Function<Throwable, ? extends CompletionStage> fn)` Returns a new CompletionStage that, when this stage completes exceptionally, is composed using the results of the supplied function applied to this stage's exception, using this stage's default asynchronous execution facility.
`default CompletionStage`	`exceptionallyComposeAsync(Function<Throwable, ? extends CompletionStage> fn, Executor executor)` Returns a new CompletionStage that, when this stage completes exceptionally, is composed using the results of the supplied function applied to this stage's exception, using the supplied Executor.
`abstract CompletionStage`	`handle(BiFunctionThrowable, ? extends U> fn)` Returns a new CompletionStage that, when this stage completes either normally or exceptionally, is executed with this stage's result and exception as arguments to the supplied function.
`abstract CompletionStage`	`handleAsync(BiFunctionThrowable, ? extends U> fn)` Returns a new CompletionStage that, when this stage completes either normally or exceptionally, is executed using this stage's default asynchronous execution facility, with this stage's result and exception as arguments to the supplied function.
`abstract CompletionStage`	`handleAsync(BiFunctionThrowable, ? extends U> fn, Executor executor)` Returns a new CompletionStage that, when this stage completes either normally or exceptionally, is executed using the supplied executor, with this stage's result and exception as arguments to the supplied function.
`abstract CompletionStage<Void>`	`runAfterBoth(CompletionStage other, Runnable action)` Returns a new CompletionStage that, when this and the other given stage both complete normally, executes the given action.
`abstract CompletionStage<Void>`	`runAfterBothAsync(CompletionStage other, Runnable action)` Returns a new CompletionStage that, when this and the other given stage both complete normally, executes the given action using this stage's default asynchronous execution facility.
`abstract CompletionStage<Void>`	`runAfterBothAsync(CompletionStage other, Runnable action, Executor executor)` Returns a new CompletionStage that, when this and the other given stage both complete normally, executes the given action using the supplied executor.
`abstract CompletionStage<Void>`	`runAfterEither(CompletionStage other, Runnable action)` Returns a new CompletionStage that, when either this or the other given stage complete normally, executes the given action.
`abstract CompletionStage<Void>`	`runAfterEitherAsync(CompletionStage other, Runnable action)` Returns a new CompletionStage that, when either this or the other given stage complete normally, executes the given action using this stage's default asynchronous execution facility.
`abstract CompletionStage<Void>`	`runAfterEitherAsync(CompletionStage other, Runnable action, Executor executor)` Returns a new CompletionStage that, when either this or the other given stage complete normally, executes the given action using the supplied executor.
`abstract CompletionStage<Void>`	`thenAccept(Consumer action)` Returns a new CompletionStage that, when this stage completes normally, is executed with this stage's result as the argument to the supplied action.
`abstract CompletionStage<Void>`	`thenAcceptAsync(Consumer action, Executor executor)` Returns a new CompletionStage that, when this stage completes normally, is executed using the supplied Executor, with this stage's result as the argument to the supplied action.
`abstract CompletionStage<Void>`	`thenAcceptAsync(Consumer action)` Returns a new CompletionStage that, when this stage completes normally, is executed using this stage's default asynchronous execution facility, with this stage's result as the argument to the supplied action.
`abstract CompletionStage<Void>`	`thenAcceptBoth(CompletionStage other, BiConsumer action)` Returns a new CompletionStage that, when this and the other given stage both complete normally, is executed with the two results as arguments to the supplied action.
`abstract CompletionStage<Void>`	`thenAcceptBothAsync(CompletionStage other, BiConsumer action)` Returns a new CompletionStage that, when this and the other given stage both complete normally, is executed using this stage's default asynchronous execution facility, with the two results as arguments to the supplied action.
`abstract CompletionStage<Void>`	`thenAcceptBothAsync(CompletionStage other, BiConsumer action, Executor executor)` Returns a new CompletionStage that, when this and the other given stage both complete normally, is executed using the supplied executor, with the two results as arguments to the supplied action.
`abstract CompletionStage`	`thenApply(Function fn)` Returns a new CompletionStage that, when this stage completes normally, is executed with this stage's result as the argument to the supplied function.
`abstract CompletionStage`	`thenApplyAsync(Function fn, Executor executor)` Returns a new CompletionStage that, when this stage completes normally, is executed using the supplied Executor, with this stage's result as the argument to the supplied function.
`abstract CompletionStage`	`thenApplyAsync(Function fn)` Returns a new CompletionStage that, when this stage completes normally, is executed using this stage's default asynchronous execution facility, with this stage's result as the argument to the supplied function.
`abstract CompletionStage`	`thenCombine(CompletionStage other, BiFunction fn)` Returns a new CompletionStage that, when this and the other given stage both complete normally, is executed with the two results as arguments to the supplied function.
`abstract CompletionStage`	`thenCombineAsync(CompletionStage other, BiFunction fn)` Returns a new CompletionStage that, when this and the other given stage both complete normally, is executed using this stage's default asynchronous execution facility, with the two results as arguments to the supplied function.
`abstract CompletionStage`	`thenCombineAsync(CompletionStage other, BiFunction fn, Executor executor)` Returns a new CompletionStage that, when this and the other given stage both complete normally, is executed using the supplied executor, with the two results as arguments to the supplied function.
`abstract CompletionStage`	`thenCompose(FunctionCompletionStage> fn)` Returns a new CompletionStage that is completed with the same value as the CompletionStage returned by the given function.
`abstract CompletionStage`	`thenComposeAsync(FunctionCompletionStage> fn, Executor executor)` Returns a new CompletionStage that is completed with the same value as the CompletionStage returned by the given function, executed using the supplied Executor.
`abstract CompletionStage`	`thenComposeAsync(FunctionCompletionStage> fn)` Returns a new CompletionStage that is completed with the same value as the CompletionStage returned by the given function, executed using this stage's default asynchronous execution facility.
`abstract CompletionStage<Void>`	`thenRun(Runnable action)` Returns a new CompletionStage that, when this stage completes normally, executes the given action.
`abstract CompletionStage<Void>`	`thenRunAsync(Runnable action, Executor executor)` Returns a new CompletionStage that, when this stage completes normally, executes the given action using the supplied Executor.
`abstract CompletionStage<Void>`	`thenRunAsync(Runnable action)` Returns a new CompletionStage that, when this stage completes normally, executes the given action using this stage's default asynchronous execution facility.
`abstract CompletableFuture`	`toCompletableFuture()` Returns a `CompletableFuture` maintaining the same completion properties as this stage.
`abstract CompletionStage`	`whenComplete(BiConsumerThrowable> action)` Returns a new CompletionStage with the same result or exception as this stage, that executes the given action when this stage completes.
`abstract CompletionStage`	`whenCompleteAsync(BiConsumerThrowable> action, Executor executor)` Returns a new CompletionStage with the same result or exception as this stage, that executes the given action using the supplied Executor when this stage completes.
`abstract CompletionStage`	`whenCompleteAsync(BiConsumerThrowable> action)` Returns a new CompletionStage with the same result or exception as this stage, that executes the given action using this stage's default asynchronous execution facility when this stage completes.

From interface


        
          java.util.concurrent.Future

`abstract boolean`	`cancel(boolean mayInterruptIfRunning)` Attempts to cancel execution of this task.
`default Throwable`	`exceptionNow()` Returns the exception thrown by the task, without waiting.
`abstract T`	`get(long timeout, TimeUnit unit)` Waits if necessary for at most the given time for the computation to complete, and then retrieves its result, if available.
`abstract T`	`get()` Waits if necessary for the computation to complete, and then retrieves its result.
`abstract boolean`	`isCancelled()` Returns `true` if this task was cancelled before it completed normally.
`abstract boolean`	`isDone()` Returns `true` if this task completed.
`default T`	`resultNow()` Returns the computed result, without waiting.
`default Future.State`	`state()`

Public constructors

CompletableFuture

Added in API level 24

public CompletableFuture ()

Creates a new incomplete CompletableFuture.

Public methods

acceptEither

Added in API level 24

public CompletableFuture<Void> acceptEither (CompletionStage other, 
                Consumer action)

Returns a new CompletionStage that, when either this or the other given stage complete normally, is executed with the corresponding result as argument to the supplied action. See the CompletionStage documentation for rules covering exceptional completion.

Parameters
`other`	`CompletionStage`: the other CompletionStage
`action`	`Consumer`: the action to perform before completing the returned CompletionStage

Returns
`CompletableFuture<Void>`	the new CompletionStage

acceptEitherAsync

Added in API level 24

public CompletableFuture<Void> acceptEitherAsync (CompletionStage other, 
                Consumer action)

Returns a new CompletionStage that, when either this or the other given stage complete normally, is executed using this stage's default asynchronous execution facility, with the corresponding result as argument to the supplied action. See the CompletionStage documentation for rules covering exceptional completion.

Parameters
`other`	`CompletionStage`: the other CompletionStage
`action`	`Consumer`: the action to perform before completing the returned CompletionStage

Returns
`CompletableFuture<Void>`	the new CompletionStage

acceptEitherAsync

Added in API level 24

public CompletableFuture<Void> acceptEitherAsync (CompletionStage other, 
                Consumer action, 
                Executor executor)

Returns a new CompletionStage that, when either this or the other given stage complete normally, is executed using the supplied executor, with the corresponding result as argument to the supplied action. See the CompletionStage documentation for rules covering exceptional completion.

Parameters
`other`	`CompletionStage`: the other CompletionStage
`action`	`Consumer`: the action to perform before completing the returned CompletionStage
`executor`	`Executor`: the executor to use for asynchronous execution

Returns
`CompletableFuture<Void>`	the new CompletionStage

allOf

Added in API level 24

public static CompletableFuture<Void> allOf (CompletableFuture... cfs)

Returns a new CompletableFuture that is completed when all of the given CompletableFutures complete. If any of the given CompletableFutures complete exceptionally, then the returned CompletableFuture also does so, with a CompletionException holding this exception as its cause. Otherwise, the results, if any, of the given CompletableFutures are not reflected in the returned CompletableFuture, but may be obtained by inspecting them individually. If no CompletableFutures are provided, returns a CompletableFuture completed with the value null.

Among the applications of this method is to await completion of a set of independent CompletableFutures before continuing a program, as in: CompletableFuture.allOf(c1, c2, c3).join();.

Parameters
`cfs`	`CompletableFuture`: the CompletableFutures

Returns
`CompletableFuture<Void>`	a new CompletableFuture that is completed when all of the given CompletableFutures complete

Throws
`NullPointerException`	if the array or any of its elements are `null`

anyOf

Added in API level 24

public static CompletableFuture<Object> anyOf (CompletableFuture... cfs)

Returns a new CompletableFuture that is completed when any of the given CompletableFutures complete, with the same result. Otherwise, if it completed exceptionally, the returned CompletableFuture also does so, with a CompletionException holding this exception as its cause. If no CompletableFutures are provided, returns an incomplete CompletableFuture.

Parameters
`cfs`	`CompletableFuture`: the CompletableFutures

Returns
`CompletableFuture<Object>`	a new CompletableFuture that is completed with the result or exception of any of the given CompletableFutures when one completes

Throws
`NullPointerException`	if the array or any of its elements are `null`

applyToEither

Added in API level 24

public CompletableFuture applyToEither (CompletionStage other, 
                Function fn)

Returns a new CompletionStage that, when either this or the other given stage complete normally, is executed with the corresponding result as argument to the supplied function. See the CompletionStage documentation for rules covering exceptional completion.

Parameters
`other`	`CompletionStage`: the other CompletionStage
`fn`	`Function`: the function to use to compute the value of the returned CompletionStage

Returns
`CompletableFuture`	the new CompletionStage

applyToEitherAsync

Added in API level 24

public CompletableFuture applyToEitherAsync (CompletionStage other, 
                Function fn, 
                Executor executor)

Returns a new CompletionStage that, when either this or the other given stage complete normally, is executed using the supplied executor, with the corresponding result as argument to the supplied function. See the CompletionStage documentation for rules covering exceptional completion.

Parameters
`other`	`CompletionStage`: the other CompletionStage
`fn`	`Function`: the function to use to compute the value of the returned CompletionStage
`executor`	`Executor`: the executor to use for asynchronous execution

Returns
`CompletableFuture`	the new CompletionStage

applyToEitherAsync

Added in API level 24

public CompletableFuture applyToEitherAsync (CompletionStage other, 
                Function fn)

Returns a new CompletionStage that, when either this or the other given stage complete normally, is executed using this stage's default asynchronous execution facility, with the corresponding result as argument to the supplied function. See the CompletionStage documentation for rules covering exceptional completion.

Parameters
`other`	`CompletionStage`: the other CompletionStage
`fn`	`Function`: the function to use to compute the value of the returned CompletionStage

Returns
`CompletableFuture`	the new CompletionStage

cancel

Added in API level 24

public boolean cancel (boolean mayInterruptIfRunning)

If not already completed, completes this CompletableFuture with a CancellationException. Dependent CompletableFutures that have not already completed will also complete exceptionally, with a CompletionException caused by this CancellationException.

Parameters
`mayInterruptIfRunning`	`boolean`: this value has no effect in this implementation because interrupts are not used to control processing.

Returns
`boolean`	`true` if this task is now cancelled

complete

Added in API level 24

public boolean complete (T value)

If not already completed, sets the value returned by get() and related methods to the given value.

Parameters
`value`	`T`: the result value

Returns
`boolean`	`true` if this invocation caused this CompletableFuture to transition to a completed state, else `false`

completeAsync

Added in API level 31

public CompletableFuture completeAsync (Supplier supplier, 
                Executor executor)

Completes this CompletableFuture with the result of the given Supplier function invoked from an asynchronous task using the given executor.

Parameters
`supplier`	`Supplier`: a function returning the value to be used to complete this CompletableFuture
`executor`	`Executor`: the executor to use for asynchronous execution

Returns
`CompletableFuture`	this CompletableFuture

completeAsync

Added in API level 31

public CompletableFuture completeAsync (Supplier supplier)

Completes this CompletableFuture with the result of the given Supplier function invoked from an asynchronous task using the default executor.

Parameters
`supplier`	`Supplier`: a function returning the value to be used to complete this CompletableFuture

Returns
`CompletableFuture`	this CompletableFuture

completeExceptionally

Added in API level 24

public boolean completeExceptionally (Throwable ex)

If not already completed, causes invocations of get() and related methods to throw the given exception.

Parameters
`ex`	`Throwable`: the exception

Returns
`boolean`	`true` if this invocation caused this CompletableFuture to transition to a completed state, else `false`

completeOnTimeout

Added in API level 31

public CompletableFuture completeOnTimeout (T value, 
                long timeout, 
                TimeUnit unit)

Completes this CompletableFuture with the given value if not otherwise completed before the given timeout.

Parameters
`value`	`T`: the value to use upon timeout
`timeout`	`long`: how long to wait before completing normally with the given value, in units of `unit`
`unit`	`TimeUnit`: a `TimeUnit` determining how to interpret the `timeout` parameter

Returns
`CompletableFuture`	this CompletableFuture

completedFuture

Added in API level 24

public static CompletableFuture completedFuture (U value)

Returns a new CompletableFuture that is already completed with the given value.

Parameters
`value`	`U`: the value

Returns
`CompletableFuture`	the completed CompletableFuture

completedStage

Added in API level 31

public static CompletionStage completedStage (U value)

Returns a new CompletionStage that is already completed with the given value and supports only those methods in interface CompletionStage.

Parameters
`value`	`U`: the value

Returns
`CompletionStage`	the completed CompletionStage

copy

Added in API level 31

public CompletableFuture copy ()

Returns a new CompletableFuture that is completed normally with the same value as this CompletableFuture when it completes normally. If this CompletableFuture completes exceptionally, then the returned CompletableFuture completes exceptionally with a CompletionException with this exception as cause. The behavior is equivalent to thenApply(x -> x). This method may be useful as a form of "defensive copying", to prevent clients from completing, while still being able to arrange dependent actions.

Returns
`CompletableFuture`	the new CompletableFuture

defaultExecutor

Added in API level 31

public Executor defaultExecutor ()

Returns the default Executor used for async methods that do not specify an Executor. This class uses the ForkJoinPool.commonPool() if it supports more than one parallel thread, or else an Executor using one thread per async task. This method may be overridden in subclasses to return an Executor that provides at least one independent thread.

Returns
`Executor`	the executor

delayedExecutor

Added in API level 31

public static Executor delayedExecutor (long delay, 
                TimeUnit unit, 
                Executor executor)

Returns a new Executor that submits a task to the given base executor after the given delay (or no delay if non-positive). Each delay commences upon invocation of the returned executor's execute method.

Parameters
`delay`	`long`: how long to delay, in units of `unit`
`unit`	`TimeUnit`: a `TimeUnit` determining how to interpret the `delay` parameter
`executor`	`Executor`: the base executor

Returns
`Executor`	the new delayed executor

delayedExecutor

Added in API level 31

public static Executor delayedExecutor (long delay, 
                TimeUnit unit)

Returns a new Executor that submits a task to the default executor after the given delay (or no delay if non-positive). Each delay commences upon invocation of the returned executor's execute method.

Parameters
`delay`	`long`: how long to delay, in units of `unit`
`unit`	`TimeUnit`: a `TimeUnit` determining how to interpret the `delay` parameter

Returns
`Executor`	the new delayed executor

exceptionNow

Added in API level 36

public Throwable exceptionNow ()

Returns the exception thrown by the task, without waiting.

This method is for cases where the caller knows that the task has already completed with an exception.

Returns
`Throwable`	the exception thrown by the task

exceptionally

Added in API level 24

public CompletableFuture exceptionally (Function<Throwable, ? extends T> fn)

Returns a new CompletionStage that, when this stage completes exceptionally, is executed with this stage's exception as the argument to the supplied function. Otherwise, if this stage completes normally, then the returned stage also completes normally with the same value.

Parameters
`fn`	`Function`: the function to use to compute the value of the returned CompletionStage if this CompletionStage completed exceptionally

Returns
`CompletableFuture`	the new CompletionStage

exceptionallyAsync

Added in API level 34

public CompletableFuture exceptionallyAsync (Function<Throwable, ? extends T> fn)

Returns a new CompletionStage that, when this stage completes exceptionally, is executed with this stage's exception as the argument to the supplied function, using this stage's default asynchronous execution facility. Otherwise, if this stage completes normally, then the returned stage also completes normally with the same value.

Parameters
`fn`	`Function`: the function to use to compute the value of the returned CompletionStage if this CompletionStage completed exceptionally

Returns
`CompletableFuture`	the new CompletionStage

exceptionallyAsync

Added in API level 34

public CompletableFuture exceptionallyAsync (Function<Throwable, ? extends T> fn, 
                Executor executor)

Returns a new CompletionStage that, when this stage completes exceptionally, is executed with this stage's exception as the argument to the supplied function, using the supplied Executor. Otherwise, if this stage completes normally, then the returned stage also completes normally with the same value.

Parameters
`fn`	`Function`: the function to use to compute the value of the returned CompletionStage if this CompletionStage completed exceptionally
`executor`	`Executor`: the executor to use for asynchronous execution

Returns
`CompletableFuture`	the new CompletionStage

exceptionallyCompose

Added in API level 34

public CompletableFuture exceptionallyCompose (Function<Throwable, ? extends CompletionStage> fn)

Returns a new CompletionStage that, when this stage completes exceptionally, is composed using the results of the supplied function applied to this stage's exception.

Parameters
`fn`	`Function`: the function to use to compute the returned CompletionStage if this CompletionStage completed exceptionally

Returns
`CompletableFuture`	the new CompletionStage

exceptionallyComposeAsync

Added in API level 34

public CompletableFuture exceptionallyComposeAsync (Function<Throwable, ? extends CompletionStage> fn, 
                Executor executor)

Returns a new CompletionStage that, when this stage completes exceptionally, is composed using the results of the supplied function applied to this stage's exception, using the supplied Executor.

Parameters
`fn`	`Function`: the function to use to compute the returned CompletionStage if this CompletionStage completed exceptionally
`executor`	`Executor`: the executor to use for asynchronous execution

Returns
`CompletableFuture`	the new CompletionStage

exceptionallyComposeAsync

Added in API level 34

public CompletableFuture exceptionallyComposeAsync (Function<Throwable, ? extends CompletionStage> fn)

Returns a new CompletionStage that, when this stage completes exceptionally, is composed using the results of the supplied function applied to this stage's exception, using this stage's default asynchronous execution facility.

Parameters
`fn`	`Function`: the function to use to compute the returned CompletionStage if this CompletionStage completed exceptionally

Returns
`CompletableFuture`	the new CompletionStage

failedFuture

Added in API level 31

public static CompletableFuture failedFuture (Throwable ex)

Returns a new CompletableFuture that is already completed exceptionally with the given exception.

Parameters
`ex`	`Throwable`: the exception

Returns
`CompletableFuture`	the exceptionally completed CompletableFuture

failedStage

Added in API level 31

public static CompletionStage failedStage (Throwable ex)

Returns a new CompletionStage that is already completed exceptionally with the given exception and supports only those methods in interface CompletionStage.

Parameters
`ex`	`Throwable`: the exception

Returns
`CompletionStage`	the exceptionally completed CompletionStage

get

Added in API level 24

public T get (long timeout, 
                TimeUnit unit)

Waits if necessary for at most the given time for this future to complete, and then returns its result, if available.

Parameters
`timeout`	`long`: the maximum time to wait
`unit`	`TimeUnit`: the time unit of the timeout argument

Returns
`T`	the result value

Throws
`CancellationException`	if this future was cancelled
`ExecutionException`	if this future completed exceptionally
`InterruptedException`	if the current thread was interrupted while waiting
`TimeoutException`	if the wait timed out

get

Added in API level 24

public T get ()

Waits if necessary for this future to complete, and then returns its result.

Returns
`T`	the result value

Throws
`CancellationException`	if this future was cancelled
`ExecutionException`	if this future completed exceptionally
`InterruptedException`	if the current thread was interrupted while waiting

getNow

Added in API level 24

public T getNow (T valueIfAbsent)

Returns the result value (or throws any encountered exception) if completed, else returns the given valueIfAbsent.

Parameters
`valueIfAbsent`	`T`: the value to return if not completed

Returns
`T`	the result value, if completed, else the given valueIfAbsent

Throws
`CancellationException`	if the computation was cancelled
`CompletionException`	if this future completed exceptionally or a completion computation threw an exception

getNumberOfDependents

Added in API level 24

public int getNumberOfDependents ()

Returns the estimated number of CompletableFutures whose completions are awaiting completion of this CompletableFuture. This method is designed for use in monitoring system state, not for synchronization control.

Returns
`int`	the number of dependent CompletableFutures

handle

Added in API level 24

public CompletableFuture handle (BiFunctionThrowable, ? extends U> fn)

Returns a new CompletionStage that, when this stage completes either normally or exceptionally, is executed with this stage's result and exception as arguments to the supplied function.

When this stage is complete, the given function is invoked with the result (or null if none) and the exception (or null if none) of this stage as arguments, and the function's result is used to complete the returned stage.

Parameters
`fn`	`BiFunction`: the function to use to compute the value of the returned CompletionStage

Returns
`CompletableFuture`	the new CompletionStage

handleAsync

Added in API level 24

public CompletableFuture handleAsync (BiFunctionThrowable, ? extends U> fn)

Returns a new CompletionStage that, when this stage completes either normally or exceptionally, is executed using this stage's default asynchronous execution facility, with this stage's result and exception as arguments to the supplied function.

Parameters
`fn`	`BiFunction`: the function to use to compute the value of the returned CompletionStage

Returns
`CompletableFuture`	the new CompletionStage

handleAsync

Added in API level 24

public CompletableFuture handleAsync (BiFunctionThrowable, ? extends U> fn, 
                Executor executor)

Returns a new CompletionStage that, when this stage completes either normally or exceptionally, is executed using the supplied executor, with this stage's result and exception as arguments to the supplied function.

Parameters
`fn`	`BiFunction`: the function to use to compute the value of the returned CompletionStage
`executor`	`Executor`: the executor to use for asynchronous execution

Returns
`CompletableFuture`	the new CompletionStage

isCancelled

Added in API level 24

public boolean isCancelled ()

Returns true if this CompletableFuture was cancelled before it completed normally.

Returns
`boolean`	`true` if this CompletableFuture was cancelled before it completed normally

isCompletedExceptionally

Added in API level 24

public boolean isCompletedExceptionally ()

Returns true if this CompletableFuture completed exceptionally, in any way. Possible causes include cancellation, explicit invocation of completeExceptionally, and abrupt termination of a CompletionStage action.

Returns
`boolean`	`true` if this CompletableFuture completed exceptionally

isDone

Added in API level 24

public boolean isDone ()

Returns true if completed in any fashion: normally, exceptionally, or via cancellation.

Returns
`boolean`	`true` if completed

join

Added in API level 24

public T join ()

Returns the result value when complete, or throws an (unchecked) exception if completed exceptionally. To better conform with the use of common functional forms, if a computation involved in the completion of this CompletableFuture threw an exception, this method throws an (unchecked) CompletionException with the underlying exception as its cause.

Returns
`T`	the result value

Throws
`CancellationException`	if the computation was cancelled
`CompletionException`	if this future completed exceptionally or a completion computation threw an exception

minimalCompletionStage

Added in API level 31

public CompletionStage minimalCompletionStage ()

Returns a new CompletionStage that is completed normally with the same value as this CompletableFuture when it completes normally, and cannot be independently completed or otherwise used in ways not defined by the methods of interface CompletionStage. If this CompletableFuture completes exceptionally, then the returned CompletionStage completes exceptionally with a CompletionException with this exception as cause.

Unless overridden by a subclass, a new non-minimal CompletableFuture with all methods available can be obtained from a minimal CompletionStage via toCompletableFuture(). For example, completion of a minimal stage can be awaited by

 minimalStage.toCompletableFuture().join();

Returns
`CompletionStage`	the new CompletionStage

newIncompleteFuture

Added in API level 31

public CompletableFuture newIncompleteFuture ()

Returns a new incomplete CompletableFuture of the type to be returned by a CompletionStage method. Subclasses should normally override this method to return an instance of the same class as this CompletableFuture. The default implementation returns an instance of class CompletableFuture.

Returns
`CompletableFuture`	a new CompletableFuture

obtrudeException

Added in API level 24

public void obtrudeException (Throwable ex)

Forcibly causes subsequent invocations of method get() and related methods to throw the given exception, whether or not already completed. This method is designed for use only in error recovery actions, and even in such situations may result in ongoing dependent completions using established versus overwritten outcomes.

Parameters
`ex`	`Throwable`: the exception

Throws
`NullPointerException`	if the exception is null

obtrudeValue

Added in API level 24

public void obtrudeValue (T value)

Forcibly sets or resets the value subsequently returned by method get() and related methods, whether or not already completed. This method is designed for use only in error recovery actions, and even in such situations may result in ongoing dependent completions using established versus overwritten outcomes.

Parameters
`value`	`T`: the completion value

orTimeout

Added in API level 31

public CompletableFuture orTimeout (long timeout, 
                TimeUnit unit)

Exceptionally completes this CompletableFuture with a TimeoutException if not otherwise completed before the given timeout.

Parameters
`timeout`	`long`: how long to wait before completing exceptionally with a TimeoutException, in units of `unit`
`unit`	`TimeUnit`: a `TimeUnit` determining how to interpret the `timeout` parameter

Returns
`CompletableFuture`	this CompletableFuture

resultNow

Added in API level 36

public T resultNow ()

Returns the computed result, without waiting.

This method is for cases where the caller knows that the task has already completed successfully, for example when filtering a stream of Future objects for the successful tasks and using a mapping operation to obtain a stream of results. lang=java : results = futures.stream() .filter(f -> f.state() == Future.State.SUCCESS) .map(Future::resultNow) .toList();

Returns
`T`	the computed result

runAfterBoth

Added in API level 24

public CompletableFuture<Void> runAfterBoth (CompletionStage other, 
                Runnable action)

Returns a new CompletionStage that, when this and the other given stage both complete normally, executes the given action. See the CompletionStage documentation for rules covering exceptional completion.

Parameters
`other`	`CompletionStage`: the other CompletionStage
`action`	`Runnable`: the action to perform before completing the returned CompletionStage

Returns
`CompletableFuture<Void>`	the new CompletionStage

runAfterBothAsync

Added in API level 24

public CompletableFuture<Void> runAfterBothAsync (CompletionStage other, 
                Runnable action)

Returns a new CompletionStage that, when this and the other given stage both complete normally, executes the given action using this stage's default asynchronous execution facility. See the CompletionStage documentation for rules covering exceptional completion.

Parameters
`other`	`CompletionStage`: the other CompletionStage
`action`	`Runnable`: the action to perform before completing the returned CompletionStage

Returns
`CompletableFuture<Void>`	the new CompletionStage

runAfterBothAsync

Added in API level 24

public CompletableFuture<Void> runAfterBothAsync (CompletionStage other, 
                Runnable action, 
                Executor executor)

Returns a new CompletionStage that, when this and the other given stage both complete normally, executes the given action using the supplied executor. See the CompletionStage documentation for rules covering exceptional completion.

Parameters
`other`	`CompletionStage`: the other CompletionStage
`action`	`Runnable`: the action to perform before completing the returned CompletionStage
`executor`	`Executor`: the executor to use for asynchronous execution

Returns
`CompletableFuture<Void>`	the new CompletionStage

runAfterEither

Added in API level 24

public CompletableFuture<Void> runAfterEither (CompletionStage other, 
                Runnable action)

Returns a new CompletionStage that, when either this or the other given stage complete normally, executes the given action. See the CompletionStage documentation for rules covering exceptional completion.

Parameters
`other`	`CompletionStage`: the other CompletionStage
`action`	`Runnable`: the action to perform before completing the returned CompletionStage

Returns
`CompletableFuture<Void>`	the new CompletionStage

runAfterEitherAsync

Added in API level 24

public CompletableFuture<Void> runAfterEitherAsync (CompletionStage other, 
                Runnable action, 
                Executor executor)

Returns a new CompletionStage that, when either this or the other given stage complete normally, executes the given action using the supplied executor. See the CompletionStage documentation for rules covering exceptional completion.

Parameters
`other`	`CompletionStage`: the other CompletionStage
`action`	`Runnable`: the action to perform before completing the returned CompletionStage
`executor`	`Executor`: the executor to use for asynchronous execution

Returns
`CompletableFuture<Void>`	the new CompletionStage

runAfterEitherAsync

Added in API level 24

public CompletableFuture<Void> runAfterEitherAsync (CompletionStage other, 
                Runnable action)

Returns a new CompletionStage that, when either this or the other given stage complete normally, executes the given action using this stage's default asynchronous execution facility. See the CompletionStage documentation for rules covering exceptional completion.

Parameters
`other`	`CompletionStage`: the other CompletionStage
`action`	`Runnable`: the action to perform before completing the returned CompletionStage

Returns
`CompletableFuture<Void>`	the new CompletionStage

runAsync

Added in API level 24

public static CompletableFuture<Void> runAsync (Runnable runnable)

Returns a new CompletableFuture that is asynchronously completed by a task running in the ForkJoinPool.commonPool() after it runs the given action.

Parameters
`runnable`	`Runnable`: the action to run before completing the returned CompletableFuture

Returns
`CompletableFuture<Void>`	the new CompletableFuture

runAsync

Added in API level 24

public static CompletableFuture<Void> runAsync (Runnable runnable, 
                Executor executor)

Returns a new CompletableFuture that is asynchronously completed by a task running in the given executor after it runs the given action.

Parameters
`runnable`	`Runnable`: the action to run before completing the returned CompletableFuture
`executor`	`Executor`: the executor to use for asynchronous execution

Returns
`CompletableFuture<Void>`	the new CompletableFuture

state

Added in API level 36

public Future.State state ()

Returns
`Future.State`	the computation state

supplyAsync

Added in API level 24

public static CompletableFuture supplyAsync (Supplier supplier)

Returns a new CompletableFuture that is asynchronously completed by a task running in the ForkJoinPool.commonPool() with the value obtained by calling the given Supplier.

Parameters
`supplier`	`Supplier`: a function returning the value to be used to complete the returned CompletableFuture

Returns
`CompletableFuture`	the new CompletableFuture

supplyAsync

Added in API level 24

public static CompletableFuture supplyAsync (Supplier supplier, 
                Executor executor)

Returns a new CompletableFuture that is asynchronously completed by a task running in the given executor with the value obtained by calling the given Supplier.

Parameters
`supplier`	`Supplier`: a function returning the value to be used to complete the returned CompletableFuture
`executor`	`Executor`: the executor to use for asynchronous execution

Returns
`CompletableFuture`	the new CompletableFuture

thenAccept

Added in API level 24

public CompletableFuture<Void> thenAccept (Consumer action)

Returns a new CompletionStage that, when this stage completes normally, is executed with this stage's result as the argument to the supplied action. See the CompletionStage documentation for rules covering exceptional completion.

Parameters
`action`	`Consumer`: the action to perform before completing the returned CompletionStage

Returns
`CompletableFuture<Void>`	the new CompletionStage

thenAcceptAsync

Added in API level 24

public CompletableFuture<Void> thenAcceptAsync (Consumer action, 
                Executor executor)

Returns a new CompletionStage that, when this stage completes normally, is executed using the supplied Executor, with this stage's result as the argument to the supplied action. See the CompletionStage documentation for rules covering exceptional completion.

Parameters
`action`	`Consumer`: the action to perform before completing the returned CompletionStage
`executor`	`Executor`: the executor to use for asynchronous execution

Returns
`CompletableFuture<Void>`	the new CompletionStage

thenAcceptAsync

Added in API level 24

public CompletableFuture<Void> thenAcceptAsync (Consumer action)

Returns a new CompletionStage that, when this stage completes normally, is executed using this stage's default asynchronous execution facility, with this stage's result as the argument to the supplied action. See the CompletionStage documentation for rules covering exceptional completion.

Parameters
`action`	`Consumer`: the action to perform before completing the returned CompletionStage

Returns
`CompletableFuture<Void>`	the new CompletionStage

thenAcceptBoth

Added in API level 24

public CompletableFuture<Void> thenAcceptBoth (CompletionStage other, 
                BiConsumer action)

Returns a new CompletionStage that, when this and the other given stage both complete normally, is executed with the two results as arguments to the supplied action. See the CompletionStage documentation for rules covering exceptional completion.

Parameters
`other`	`CompletionStage`: the other CompletionStage
`action`	`BiConsumer`: the action to perform before completing the returned CompletionStage

Returns
`CompletableFuture<Void>`	the new CompletionStage

thenAcceptBothAsync

Added in API level 24

public CompletableFuture<Void> thenAcceptBothAsync (CompletionStage other, 
                BiConsumer action, 
                Executor executor)

Returns a new CompletionStage that, when this and the other given stage both complete normally, is executed using the supplied executor, with the two results as arguments to the supplied action. See the CompletionStage documentation for rules covering exceptional completion.

Parameters
`other`	`CompletionStage`: the other CompletionStage
`action`	`BiConsumer`: the action to perform before completing the returned CompletionStage
`executor`	`Executor`: the executor to use for asynchronous execution

Returns
`CompletableFuture<Void>`	the new CompletionStage

thenAcceptBothAsync

Added in API level 24

public CompletableFuture<Void> thenAcceptBothAsync (CompletionStage other, 
                BiConsumer action)

Returns a new CompletionStage that, when this and the other given stage both complete normally, is executed using this stage's default asynchronous execution facility, with the two results as arguments to the supplied action. See the CompletionStage documentation for rules covering exceptional completion.

Parameters
`other`	`CompletionStage`: the other CompletionStage
`action`	`BiConsumer`: the action to perform before completing the returned CompletionStage

Returns
`CompletableFuture<Void>`	the new CompletionStage

thenApply

Added in API level 24

public CompletableFuture thenApply (Function fn)

Returns a new CompletionStage that, when this stage completes normally, is executed with this stage's result as the argument to the supplied function.

This method is analogous to Optional.map and Stream.map.

See the CompletionStage documentation for rules covering exceptional completion.

Parameters
`fn`	`Function`: the function to use to compute the value of the returned CompletionStage

Returns
`CompletableFuture`	the new CompletionStage

thenApplyAsync

Added in API level 24

public CompletableFuture thenApplyAsync (Function fn, 
                Executor executor)

Returns a new CompletionStage that, when this stage completes normally, is executed using the supplied Executor, with this stage's result as the argument to the supplied function. See the CompletionStage documentation for rules covering exceptional completion.

Parameters
`fn`	`Function`: the function to use to compute the value of the returned CompletionStage
`executor`	`Executor`: the executor to use for asynchronous execution

Returns
`CompletableFuture`	the new CompletionStage

thenApplyAsync

Added in API level 24

public CompletableFuture thenApplyAsync (Function fn)

Returns a new CompletionStage that, when this stage completes normally, is executed using this stage's default asynchronous execution facility, with this stage's result as the argument to the supplied function. See the CompletionStage documentation for rules covering exceptional completion.

Parameters
`fn`	`Function`: the function to use to compute the value of the returned CompletionStage

Returns
`CompletableFuture`	the new CompletionStage

thenCombine

Added in API level 24

public CompletableFuture thenCombine (CompletionStage other, 
                BiFunction fn)

Returns a new CompletionStage that, when this and the other given stage both complete normally, is executed with the two results as arguments to the supplied function. See the CompletionStage documentation for rules covering exceptional completion.

Parameters
`other`	`CompletionStage`: the other CompletionStage
`fn`	`BiFunction`: the function to use to compute the value of the returned CompletionStage

Returns
`CompletableFuture`	the new CompletionStage

thenCombineAsync

Added in API level 24

public CompletableFuture thenCombineAsync (CompletionStage other, 
                BiFunction fn, 
                Executor executor)

Returns a new CompletionStage that, when this and the other given stage both complete normally, is executed using the supplied executor, with the two results as arguments to the supplied function. See the CompletionStage documentation for rules covering exceptional completion.

Parameters
`other`	`CompletionStage`: the other CompletionStage
`fn`	`BiFunction`: the function to use to compute the value of the returned CompletionStage
`executor`	`Executor`: the executor to use for asynchronous execution

Returns
`CompletableFuture`	the new CompletionStage

thenCombineAsync

Added in API level 24

public CompletableFuture thenCombineAsync (CompletionStage other, 
                BiFunction fn)

Returns a new CompletionStage that, when this and the other given stage both complete normally, is executed using this stage's default asynchronous execution facility, with the two results as arguments to the supplied function. See the CompletionStage documentation for rules covering exceptional completion.

Parameters
`other`	`CompletionStage`: the other CompletionStage
`fn`	`BiFunction`: the function to use to compute the value of the returned CompletionStage

Returns
`CompletableFuture`	the new CompletionStage

thenCompose

Added in API level 24

public CompletableFuture thenCompose (FunctionCompletionStage> fn)

Returns a new CompletionStage that is completed with the same value as the CompletionStage returned by the given function.

When this stage completes normally, the given function is invoked with this stage's result as the argument, returning another CompletionStage. When that stage completes normally, the CompletionStage returned by this method is completed with the same value.

To ensure progress, the supplied function must arrange eventual completion of its result.

This method is analogous to Optional.flatMap and Stream.flatMap.

See the CompletionStage documentation for rules covering exceptional completion.

Parameters
`fn`	`Function`: the function to use to compute another CompletionStage

Returns
`CompletableFuture`	the new CompletionStage

thenComposeAsync

Added in API level 24

public CompletableFuture thenComposeAsync (FunctionCompletionStage> fn)

Returns a new CompletionStage that is completed with the same value as the CompletionStage returned by the given function, executed using this stage's default asynchronous execution facility.

To ensure progress, the supplied function must arrange eventual completion of its result.

See the CompletionStage documentation for rules covering exceptional completion.

Parameters
`fn`	`Function`: the function to use to compute another CompletionStage

Returns
`CompletableFuture`	the new CompletionStage

thenComposeAsync

Added in API level 24

public CompletableFuture thenComposeAsync (FunctionCompletionStage> fn, 
                Executor executor)

Returns a new CompletionStage that is completed with the same value as the CompletionStage returned by the given function, executed using the supplied Executor.

To ensure progress, the supplied function must arrange eventual completion of its result.

See the CompletionStage documentation for rules covering exceptional completion.

Parameters
`fn`	`Function`: the function to use to compute another CompletionStage
`executor`	`Executor`: the executor to use for asynchronous execution

Returns
`CompletableFuture`	the new CompletionStage

thenRun

Added in API level 24

public CompletableFuture<Void> thenRun (Runnable action)

Returns a new CompletionStage that, when this stage completes normally, executes the given action. See the CompletionStage documentation for rules covering exceptional completion.

Parameters
`action`	`Runnable`: the action to perform before completing the returned CompletionStage

Returns
`CompletableFuture<Void>`	the new CompletionStage

thenRunAsync

Added in API level 24

public CompletableFuture<Void> thenRunAsync (Runnable action, 
                Executor executor)

Returns a new CompletionStage that, when this stage completes normally, executes the given action using the supplied Executor. See the CompletionStage documentation for rules covering exceptional completion.

Parameters
`action`	`Runnable`: the action to perform before completing the returned CompletionStage
`executor`	`Executor`: the executor to use for asynchronous execution

Returns
`CompletableFuture<Void>`	the new CompletionStage

thenRunAsync

Added in API level 24

public CompletableFuture<Void> thenRunAsync (Runnable action)

Returns a new CompletionStage that, when this stage completes normally, executes the given action using this stage's default asynchronous execution facility. See the CompletionStage documentation for rules covering exceptional completion.

Parameters
`action`	`Runnable`: the action to perform before completing the returned CompletionStage

Returns
`CompletableFuture<Void>`	the new CompletionStage

toCompletableFuture

Added in API level 24

public CompletableFuture toCompletableFuture ()

Returns this CompletableFuture.

Returns
`CompletableFuture`	this CompletableFuture

toString

Added in API level 24

public String toString ()

Returns a string identifying this CompletableFuture, as well as its completion state. The state, in brackets, contains the String "Completed Normally" or the String "Completed Exceptionally", or the String "Not completed" followed by the number of CompletableFutures dependent upon its completion, if any.

Returns
`String`	a string identifying this CompletableFuture, as well as its state

whenComplete

Added in API level 24

public CompletableFuture whenComplete (BiConsumerThrowable> action)

Returns a new CompletionStage with the same result or exception as this stage, that executes the given action when this stage completes.

When this stage is complete, the given action is invoked with the result (or null if none) and the exception (or null if none) of this stage as arguments. The returned stage is completed when the action returns.

Unlike method handle, this method is not designed to translate completion outcomes, so the supplied action should not throw an exception. However, if it does, the following rules apply: if this stage completed normally but the supplied action throws an exception, then the returned stage completes exceptionally with the supplied action's exception. Or, if this stage completed exceptionally and the supplied action throws an exception, then the returned stage completes exceptionally with this stage's exception.

Parameters
`action`	`BiConsumer`: the action to perform

Returns
`CompletableFuture`	the new CompletionStage

whenCompleteAsync

Added in API level 24

public CompletableFuture whenCompleteAsync (BiConsumerThrowable> action, 
                Executor executor)

Returns a new CompletionStage with the same result or exception as this stage, that executes the given action using the supplied Executor when this stage completes.

Unlike method handleAsync, this method is not designed to translate completion outcomes, so the supplied action should not throw an exception. However, if it does, the following rules apply: If this stage completed normally but the supplied action throws an exception, then the returned stage completes exceptionally with the supplied action's exception. Or, if this stage completed exceptionally and the supplied action throws an exception, then the returned stage completes exceptionally with this stage's exception.

Parameters
`action`	`BiConsumer`: the action to perform
`executor`	`Executor`: the executor to use for asynchronous execution

Returns
`CompletableFuture`	the new CompletionStage

whenCompleteAsync

Added in API level 24

public CompletableFuture whenCompleteAsync (BiConsumerThrowable> action)

Returns a new CompletionStage with the same result or exception as this stage, that executes the given action using this stage's default asynchronous execution facility when this stage completes.

Parameters
`action`	`BiConsumer`: the action to perform

Returns
`CompletableFuture`	the new CompletionStage

Content and code samples on this page are subject to the licenses described in the Content License. Java and OpenJDK are trademarks or registered trademarks of Oracle and/or its affiliates.

Last updated 2025-03-13 UTC.

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CompletableFuture

Summary

Nested classes

Public constructors

Public methods

Inherited methods

Public constructors

CompletableFuture

Public methods

acceptEither

acceptEitherAsync

acceptEitherAsync

allOf

anyOf

applyToEither

applyToEitherAsync

applyToEitherAsync

cancel

complete

completeAsync

completeAsync

completeExceptionally

completeOnTimeout

completedFuture

completedStage

copy

defaultExecutor

delayedExecutor

delayedExecutor

exceptionNow

exceptionally

exceptionallyAsync

exceptionallyAsync

exceptionallyCompose

exceptionallyComposeAsync

exceptionallyComposeAsync

failedFuture

failedStage

get

get

getNow

getNumberOfDependents

handle

handleAsync

handleAsync

isCancelled

isCompletedExceptionally

isDone

join

minimalCompletionStage

newIncompleteFuture

obtrudeException

obtrudeValue

orTimeout

resultNow

runAfterBoth

runAfterBothAsync

runAfterBothAsync

runAfterEither

runAfterEitherAsync

runAfterEitherAsync

runAsync

runAsync

state

supplyAsync

supplyAsync

thenAccept

thenAcceptAsync

thenAcceptAsync

thenAcceptBoth

thenAcceptBothAsync

thenAcceptBothAsync

thenApply

thenApplyAsync

thenApplyAsync

thenCombine

thenCombineAsync

thenCombineAsync

thenCompose

thenComposeAsync