Sun Microsystems, obviously
Android was released in September 2008, with the first phone in November. At that time Sun was in acquisition talks with IBM (and maybe HP), which fell through in 3/09. In 4/09 -- about six months after Android was released -- they announced their agreement with Oracle[1]. That's hardly enough time to even prepare such a lawsuit, let alone carry it through, and obviously Sun had much greater concerns at the time.
[1]: Because no such action had ever gone un-sued.
[2]: see https://en.wikipedia.org/wiki/Sun_acquisition_by_Oracle#Hist...
In the meantime, though, it seems like Android is about to adopt Oracle's OpenJDK, under the open-source license granted by Oracle.
FWIW, Google does it too: https://www.scribd.com/doc/40513712/Google-v-US-Complaint
And I understand, the cases are not the same at all, but it highlights that Oracle is hardly the only tech company who will take to the courts to help themselves make money.
Shall I go on?