If capabilities (Capture Catching) proves to be very useful (and really solves the problems it claims to be able to solve) then it's likely that Java will also implement it, no? So... in about 8-15 years?
I doubt it. For Capture Catching of Capabilities to work, you need some of the unique sauce practically only Scala has. E.g. Contextual functions or path-dependent types. Java almost certainly won't adopt these.