Seven years after Oracle filed the first legal action against Google in a dispute over use of components in the Java programming language, a new stage in the case began in federal court in San Francisco.

Jury selection started May 9 in Day 1 of what has become one of the longest-running copyright infringement lawsuits ever in the U.S. court system.

Jurors selected by attorneys from both sides will hear a rehash of the complicated details in the dispute over how elements of the Java programming language—created by Sun Microsystems in the early '90s and acquired by Oracle in 2010—made their way into Google's Android mobile device operating system.

Android is the most prevalent OS in the world, and Oracle believes it deserves a piece of profit from all that success. More than 1 billion devices running Android shipped in 2014 alone; there are about 19,000 distinct devices that use the operating system.

Oracle: Android Borrows Heavily From Java

Oracle contends that Android borrows heavily from the open-source Java language without obtaining licenses and is asking the court for $9.3 billion in copyright damages and lost revenue.

"It copied thousands of lines of Oracle's computer code as well as the structure, sequence, and organization of the 37 Java API packages into Android," Oracle lawyers wrote in a trial brief.

Oracle originally sued Google in 2010 for using 37 Java application programming interfaces (APIs) in its Android mobile operating system without first obtaining a license for the technology from Oracle. At the time, Oracle sought $1 billion in damages from Google.

The case first went to trial in 2012 and ended with a jury deciding that Google had infringed on Oracle's APIs, but it remained undecided on whether that infringement constituted fair use of Oracle's technology. The trial judge in the case, Judge William Alsup, later ruled the specific Java APIs at the center of the controversy did not have copyright protections and Google therefore had not infringed on anything.

Java APIs Ruled Protected by Copyright Laws

Upon Oracle's appeal, however, a federal appellate court reversed that ruling in 2014 and held that the Oracle APIs were protected under the U.S. Copyright Act. But that court left it up to the lower court to decide whether Google's actions constituted fair use as defined under the Copyright Act.

So the case is back in federal court in San Francisco. It is expected to take up several weeks on the court calendar.

A legal determination regarding what can and cannot be protected by copyright in software development is very important to the business of IT. The outcome of this case, even though it is specifically about Java APIs, has long-term repercussions—not just for Google, but also the entire software industry. This is because all APIs act as a common language among developers to enable faster, more efficient development.

APIs are specifications that allow applications to communicate with each other. For example, when someone types into a document and then hits the “print” command, an API is being used that enables the word processor to talk to the printer driver, even though all the software was written by different people.

Fair Use of APIs Now the Issue at Stake

The major argument until June 29, 2015—the last time the case was in court—was whether APIs, in Java or in any other programming language, are considered either software tools or techniques in creating software. A technique cannot be copyrighted. Since the highest court possible (the federal appellate court in May 2014) has ruled that the Java APIs are indeed copyrightable, that important part of the case has been decided.

What will be left to this court to decide is whether Google demonstrated fair use of the APIs that now have been determined to belong to Oracle's intellectual property bank.

Fair use in the context of commercial software is a high bar to reach, but Google appears confident it can defend its position. At a high level, a fair use is any copying of copyrighted material done for a limited and "transformative" purpose, such as to comment upon, criticize or parody a copyrighted work.

Oracle is clear in its belief that the Java APIs were used for commercial purposes in the development of Android, and that there was no fair use of those descriptions involved.