For people actually working with JVM and the languages on top of it, nobody really is worried about Oracle. The way the licensing is set up, they just don't have enough power to coerce people to use their version. It would kind of be like the SCO case if they came after it. I think they went after Google for Android simply to protect their IP, and that one they even "lost" (which detracts also from their possible future lawsuit on enforcing Java licensing)