They will be employed to work on the JDK: there are plenty of companies that are already involved in Java and employ people to work on it outside of Oracle.
Hypothetically IBM, Red Hat, Google and the other non-Hotspot VM makers could band together and fork Java successfully - hell, a even a bank or 3 will want in on the action. They will have to name it something else and prepare for the inevitable epic lawsuit, but funding people to work in the JDK will nor be a problem.
IBM sees future in Swift LOB apps and Go on blockchain related efforts. Also with open sourcing of their own J9 components they would be even less inclined to participate in OpenJDK fork or some such
Redhat sees Ceylon on apps side and with all this containerization thing going on, may be quite a bit of Go.
Google of course is betting big on Dart on apps side and Go on infra side.
For Banks I do not see any issue at all to either pay Oracle or Azul to get commercially supported JDK. Their main unique requirements are either high-perf GC(Azul) or high perf collections which they anyway write for themselves.
Dart is dead (or at least dormant). Google is pushing MS'ss Typescript very hard with Angular 2.
It is about 1M+ lines of highly optimized C/C++ code and 4M lines of Java code. So it is not like a package or a library that a dozen or contributor manage well. And Considering payment is the core issue here I do not know how highly paid people will be made to work on JDK.