To simplify life working with Java 8+ futures, there's a Spotify library called completable-futures.
It contains some useful utility methods, described in more detail below
Sometimes (through no fault of you own, I'm sure!) you may end up with something like:
CompletableFuture<CompletableFuture<T>> future which may be annoying to work with.
Fortunately, it's not very difficult to convert that to CompletableFuture<T> future2.
All you need to do is apply thenCompose(value -> value) (composing with the identity function).
This has been wrapped as dereference - naming was chosen to correspond to the equivalent function in Google Guava.
These functions can simplify getting the value or exception from a completed future, without risking blocking the thread.
This is typically useful in code that needs the value from known completed futures or in unit tests.
exceptionallyCompose() was introduced to cover the usecase of handling a failure by doing more asynchronous work.
While the Java 8 API lets you handle a successful future and compose it (with thenCompose) there is no such
equivalent for handling exception. This convenience method is very simple to implement.
Implementation: ExceptionallyCompose
It also includes some utility functions to combine multiple futures in a safe way, avoiding manual error-prone calls to get or join.
Check out the github page to learn about more utilities.