Optional is not good at all. It is not enforced by the compiler and optional itself can be null. In hot loops it can allocate like crazy. We need compiler support to enforce nullability and to get null into the type system.
In a codebase heavily reliant on Optional it can be worthwhile to install NullAway just for the benefit of banishing that particular source of null. That doesn't help with dependencies of course (unless you are certain they also use a nullability checker), and calls to those will have to be wrapped with your favorite `null -> Optional.empty()` helper function.
The pain with allocation is temporary. It is one of the candidates to become value types.
