Sample code for short circuiting CompletableFuture chain based on solution @ https://stackoverflow.com/questions/48145264/shortcut-chain-of-completablefuture-based-on-a-condition.

ShortCircuitCompletableFutureChain.java

@RunWith(JUnit4.class)
public class ExceptionHandlingTests {

    class ShortCircuitCF<T> {
        final CompletableFuture<T> result = new CompletableFuture<>();
        final CompletableFuture<T> notCompleted = new CompletableFuture<>();
        CompletableFuture<T> propagate(T value) {
            result.complete(value);
            return notCompleted;
        }
        CompletableFuture<T> complete(T value) {
            return CompletableFuture.completedFuture(value);
        }
        CompletableFuture<T> getResult() {
            return result;
        }
    }

    @Test
    public void test1() {
        for(int shortCutAt: IntStream.range(0, 4).toArray()) {
            System.out.println("Example execution with "
                + (shortCutAt == 0 ? "no shortcut" : "shortcut at " + shortCutAt));

            ShortCircuitCF<Integer> result = new ShortCircuitCF<>();
            CompletableFuture.completedFuture(null).thenCompose(justVoid -> { // runAsync
                System.out.println("Completing result1. Result: " + result.getResult().isDone());
                if (shortCutAt == 1) {
                    return result.propagate(10);
                }
                return result.complete(null);
            }).thenCompose(x -> {
                System.out.println("Completing result2. Result: " + result.getResult().isDone());
                if (shortCutAt == 2) {
                    return result.propagate(10);
                }
                return result.complete(5);
            }).thenCompose(x -> {
                System.out.println("Completing result3. Result: " + result.getResult().isDone());
                if (shortCutAt == 3) {
                    return result.propagate(10);
                }
                return result.complete(5);
            }).applyToEither(result.getResult(), Function.identity())
                .thenAccept(fr -> System.out.println("final result: " + fr));

            System.out.println();
        }
    }
}