The Court held that Google's copying of the Java SE API was a fair use. In a 6-2 opinion, Justice Breyer considered the four guiding factors in the Copyright Act's fair use provisions: (1) purpose and character of the use; (2) nature of the copyrighted work; (3) the amount and substantiality of the portion used in relation to the copyrighted work as a whole; and (4) the effect of the use upon the potential market for or value of the copyrighted work. In finding fair use, the Court reasoned the following: (1) the copied lines of code are part of a user interface that provides a way for programmers to access prewritten computer code through the use of simple commands; (2) Google's limited copying of the API is a transformative use; (3) Google's copying of 11,500 lines of code was only 0.4% of the entire API; and (4) Google's Android platform is not a market substitute for Jave SE and the copyright holder would benefit from reimplementation of its interface into a different market.
Full text of the opinion is available here.