Everyone seems to have forgotten that Sun licensed Java under an open license that would have allowed Google to use these interfaces without issue, if they had met certain criteria for supporting the full Java platform. Google essential thought "Well, we have too much bloat, and these parts are totally unneeded in our platform, so we're going to strip them out."
I seem to recall Sun refusing to allow Apache Harmony's implementation of the Java stdlib to be certified, or didn't allow access to the TCK or something like that. It may have seemed at the time like trying for an official certification for Android was pointless.
And adding to that, the entire enforcement mechanism was through trademarks, not copyright. And trademarks are about the only IP construct not brought up in this case.
Oracle's lawsuit is so bad-faith it is laughable.