It is not unreasonable, but it was unexpected; just like Serkan agreed. And in the digg post, the submitter's comment is: "Didn't see that one coming" :)
I can understand it, because the current commercial-opensource hybrid status of java is just like how MySQL is running for years. Probably, sun has foreseen more profit in this kind of work model.
Through a software guy's eye, I can tell that MySQL will strenghten its connections with Java, and it will implement/stabilize features which java used to supply from Oracle. Because of their strong relationship in the industry, this is something important for Oracle, as well.