There&#x27;s a strong fair use defense for interoperability (<i>Sony v Connectix</i>). In the hypothetical situation that someone claimed copyright on TCP&#x2F;IP, presumably that would be a strong enough defense.<p>Google is in difficulty here because they didn&#x27;t use Java for purposes of interoperability; their version isn&#x27;t even compatible.  If they had, Oracle would have no case.<p>The appeals court left open the question of whether Java being <i>easier for developers</i> because they already know Java counts as a fair use defense.<p>It might count, and then Google is free.<p><i>If Oracle wins then in a way this might actually be good for open source; software developers would seek out the path of least resistance: APIs that could be licensed freely.</i><p>That is why the FSF supported Oracle before the supreme court.