Java Basic Tutorial

Java Flow Control

Java Array

Java Object-Oriented Programming (I)

Java Object-Oriented Programming (II)

Java Object-Oriented Programming (III)

Java Exception Handling

Java List (List)

Java Queue (Queue)

Java Map Collection

Java Set Collection

Java Input and Output (I/O)

Java Reader/Writer

Java 9 Improved CompletableFuture API

Java 9 New Features

Java 8 Introduces the CompletableFuture<T> class, which may be the explicit completion version of java.util.concurrent.Future<T> (with its value and state set), or may be used as java.util.concurrent.CompleteStage. Supports triggering some dependent functions and actions when the future is completed. Java 9 SomeCompletableFuture are introduced:

Java 9 Improvements to CompletableFuture Improvements made:

Supports delays and timeouts
Enhances support for subclassing
New factory method

Supports delays and timeouts

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

in timeoutUnits in java.util.concurrent.Timeunits units in, such as MILLISECONDS), completes this CompletableFutrue with the given value. Returns this CompletableFutrue.

public　CompletableFuture<T>　orTimeout(long　timeout,　TimeUnit　unit)

If the CompletableFutrue is not completed within the given timeout, complete this CompletableFutrue with java.util.concurrent.TimeoutException, and return this CompletableFutrue.

enhance support for subclassing

has made many improvements to CompletableFuture can be inherited more simply. For example, you might want to override the new public Executor defaultExecutor() method to replace the default executor.

Another new method that makes subclassing easier is:

public　<U>　CompletableFuture<U>　newIncompleteFuture()

New factory method

Java 8Introduces the CompletableFuture completedFuture(U value) factory method to return a CompletableFuture that has already been completed with the given value. Java 9supplements this method with a new CompletableFuture failedFuture(Throwable ex) that can return a CompletableFuture that completes with the given exception.

In addition to this, Java 9 introduced the following pair of stages-oriented factory methods, returning completed or exceptionally completed completion stages:

CompletionStage completedStage(U value): Returns a new CompletionStage that completes with the specified value, and only supports the interfaces within CompletionStage
CompletionStage failedStage(Throwable ex): Returns a new CompletionStage that completes with the specified exceptionCompletionStage , and only supports CompletionStage interfaces.