How to create a completed future in java

Question

What is the best way to construct a completed future in Java? I have implemented my own CompletedFuture below, but was hoping something like this that already exist

Answer 1

FutureTask ft = new FutureTask<>(() -> "foo");
ft.run();

System.out.println(ft.get());

will print out "foo";

You can also have a Future that throws an exception when get() is called:

FutureTask ft = new FutureTask<>(() -> {throw new RuntimeException("exception!");});
ft.run();