Google infringed Oracle's copyrighted Java APIs when it created its Android operating system, a jury in San Francisco decided on Monday. But Google did not violate Oracle's Java documentation copyrights, the jury found.

Delivering a partial verdict after more than four days of deliberation, the jury could not agree on whether Google's use of Oracle's APIs was defensible as fair use.

Here's how Oracle's legal team graphically depicted the issue to the jury:

The test for whether infringement is allowable as fair use depends on the purpose of the copying, the creativity of the copied work, the quality and quantity of copying, and the effect the copy has on the market for the original.

In response to the incompleteness of the jury's ruling, Google moved for a mistrial. The judge hearing the case, William Alsup, will consider Google's argument in support of its motion later this week.

The trial, pending since last August when Oracle filed its lawsuit against Google, began in mid-April and is expected to continue through May: Oracle's two patent claims have yet to be considered. Oracle initially sought $1 billion in damages. Presently, it appears Oracle is unlikely to win any more than $100 million, even if it prevails in its patent claims.

Google's copyright infringement--nine lines of code in the rangeCheck method in TimSort.java and ComparableTimSort.Java, code since excised from Android--may not by itself be enough for Oracle to win significant damages. After the jury delivered its verdict and left the room temporarily, Judge Alsup rejected Oracle counsel David Boies's claim for "infringer's profits" from the nine copied lines as "bordering on the ridiculous." The amount of any penalty imposed on Google won't be known until the conclusion of the patent phase of the trial, which began on Monday immediately following the partial verdict.

[ What is the possible fallout for developers from this case? Read Oracle And The End Of Programming As We Know It . ]

Judge Alsup has also indicated that he will rule on whether APIs can be copyrighted if infringement has been found. Google insists APIs cannot be copyrighted and a recent EU court decision supports that view. Last week, the Court of Justice of the European Union ruled in SAS Institute Inc. v World Programming Ltd. that neither the functionality of computer program nor the format of its data files are expressive enough to merit copyright protection.

"We appreciate the jury's efforts, and know that fair use and infringement are two sides of the same coin," Google said in an emailed statement. "The core issue is whether the APIs here are copyrightable, and that's for the court to decide. We expect to prevail on this issue and Oracle's other claims."

Oracle also thanked the jury for its service in a statement that cast Google as a license scofflaw. "The overwhelming evidence demonstrated that Google knew it needed a license and that its unauthorized fork of Java in Android shattered Java's central write once run anywhere principle," the company said. "Every major commercial enterprise--except Google--has a license for Java and maintains compatibility to run across all computing platforms."

The infringement ruling comes at a time when Google faces the imminent possibility of formal antitrust investigations of its search business in the U.S, Europe, Asia, and South America.

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