completable-future

completable-future

Simulate the execution of long-running work and show the power of CompletableFuture to execute that work concurrently.

Instructions

Follow these instructions to run the demo program:

1. Use Java 21
2. Run the program:

   • java src/dgroomes/CompletableFuturesMain.java

   • You should see output like this:

     Executing the program with an implementation that uses synchronously executed simulated work. In other words, *no concurrency*.
     Performed a small amount of work (1 second)
     Performed a medium amount of work (2 seconds)
     Performed a large amount of work (4 seconds)
     Finished. Execution time: PT7.015796S
     Executing the program with an implementation that kicks off simulated work concurrently. Notice how it executes quicker than before.
     Performed a small amount of work (1 second)
     Performed a medium amount of work (2 seconds)
     Performed a large amount of work (4 seconds)
     Finished. Execution time: PT4.005475S

Reference

• CompletableFuture for Asynchronous Programming in Java 8