Because of all ways to fill in the "Hope _____ doesn't sue" plan, "Oracle" must be in the top 5 worst companies to fill in the blank with in the tech industry.
The real question is whether Oracle could convince a jury. It is hard to imagine what their argument would be. Then again, I would have never imagined that they would use copyright law over APIs to attack Google's use of Java.
The real problem here is that Oracle is the sort of company that does "test it in court". Is Canonical really big enough to be able to afford this level of risk? Even if they win I would be surprised if they managed to talk the judge into awarding them lawyer costs from Oracle. There's definitely enough ambiguity here that it wouldn't be a stupid suit. Legally, anyhow.
https://softwarefreedom.org/resources/2016/linux-kernel-cddl...
Perhaps you are confusing them with SFC: