The ongoing legal saga known as the Oracle-Google copyright battle took a huge leap Wednesday when Oracle claimed the last six Android operating systems are "infringing Oracle's copyrights in the Java platform."

That's according to the latest paperwork (PDF) Oracle filed in the five-year-old closely watched case that so far has resulted in the determination that Application Programming Interfaces (APIs) are, indeed, copyrightable.

Oracle amended its suit, which had been mired in litigation and appeals. It now names Android operating systems Gingerbread, Honeycomb, Ice Cream Sandwich, Jelly Bean, KitKat, and Lollipop. These are the operating systems that came after Froyo, when the suit was filed in 2010.

Oracle wants unspecified monetary damages and a judge's order blocking Google "from continued acts of infringement of the Java platform copyrights."

The latest legal brouhaha comes two months after the Supreme Court declined to review Google's contentions that assigning copyright to APIs—which enable programs to talk to one another—sets a dangerous precedent and allows "copyright monopolies over the basic building blocks of computer design and programming." (PDF)

In 2012, a federal judge in San Francisco largely sided with Google and said API code could not be copyrighted. Then, US District Judge William Alsup ruled that even though Google could have rearranged "the various methods under different groupings among the various classes and packages," the overall name tree is "a utilitarian and functional set of symbols, each to carry out a pre-assigned function... Duplication of the command structure is necessary for interoperability."

A federal appeals court reversed Alsup and said that the "declaring code and the structure, sequence, and organization of the API packages are entitled to copyright protection." But it was not a complete victory for Oracle. The appeals court ordered litigation before Alsup to determine whether Google has a fair use right to use the code without paying Oracle a licensing fee.

That said, Oracle's latest filing throws a monkey wrench of sorts into the legal process because the newest allegations will have to be litigated as well. And if those six Android operating systems are found to be infringing, the question of whether Google has a fair use defense to infringement is also likely to play itself out.

Complicating matters more, however, is the fact that there's no clear answer as to what constitutes fair use. As we've previously reported, it's decided on a case-by-case basis. According to the US Copyright Office:

"The distinction between what is fair use and what is infringement in a particular case will not always be clear or easily defined. There is no specific number of words, lines, or notes that may safely be taken without permission. Acknowledging the source of the copyrighted material does not substitute for obtaining permission."

Google did not immediately respond for comment.