What is CompletableFuture.orTimeout() in Java?

Overview

orTimeout() is an instance method of the CompletableFuture which is used to exceptional timeout if the future is not completed within the given period of time.

Once the waiting period is over, the method throws an exception. This method was introduced in Java version 9.

The orTimeout method is defined in the CompletableFuture class. The class is defined in the java.util.concurrent package. To import the class, check the following import statement:

import java.util.concurrent.CompletableFuture;

Syntax

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

Parameters

long timeout: The maximum amount of time to wait.
TimeUnit unit: The unit of time.

Return value

This method returns the same CompletableFuture on which this method is applied.

import java.util.concurrent.*;
public class Main {
    static void sleep(int millis){
        try {
            Thread.sleep(millis);
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
    public static void main(String[] args) throws ExecutionException, InterruptedException {
        CompletableFuture<String> completableFuture = CompletableFuture.supplyAsync(() -> {
            sleep(4000);
            return "Hello-Educative";
        });
        long timeOutValue = 1;
        TimeUnit timeUnit = TimeUnit.SECONDS;
        completableFuture.orTimeout(timeOutValue, timeUnit).get();
    }
}

What is CompletableFuture.orTimeout() in Java?

Overview

Syntax

Parameters

Return value

Code

Explanation