The ruling on Thursday from a San Francisco federal judge is the latest blow to Oracle in its lawsuit against Google. It is one of several intellectual property cases between tech giants over smartphones and tablets using Google's Android operating system.

Apple is scheduled for trial in U.S. courts against Google's Motorola Mobility unit in June, and against Samsung in July. However, Oracle's lawsuit against Google, filed in 2010, was the first in the smartphone wars to go before a jury.

The case examined whether computer language that connects programs and operating systems - known as application programming interfaces, or APIs - can be copyrighted. In a trial that began last month, Oracle claimed Google's Android tramples on its rights to the structure of 37 Java APIs.

Google argued it did not violate Oracle's patents and that Oracle cannot copyright APIs for Java, an open-source or publicly available software language. Android is the best-selling smartphone operating system around the world.

Oracle sought roughly $1 billion on its copyright claims, but the jury deadlocked on a key copyright issue. They then found that Google did not infringe two of Oracle's patents, which ended the trial last week before damages could be considered.

Meanwhile, U.S. District Judge William Alsup had deferred a legal ruling on the ability to copyright 37 Java APIs until after the trial.

His ruling on Thursday likely eliminates the ability of Oracle to seek an immediate retrial against Google in San Francisco federal court.

Oracle spokeswoman Deborah Hellinger said the company will "vigorously appeal" Alsup's order. "This ruling, if permitted to stand, would undermine the protection for innovation and invention in the United States," Hellinger wrote in an email.

Alsup's written order does not address whether all Java APIs are free to use without a license - or whether the structure of any computer program may be stolen.

"Rather, it holds on the specific facts of this case, the particular elements replicated by Google were free for all to use," Alsup wrote.

Google spokesman Jim Prosser said the decision upholds the principle that open computer languages are essential for software development.

"It's a good day for collaboration and innovation," Prosser said.

The case in U.S. District Court, Northern District of California is Oracle America, Inc v. Google Inc, 10-3561.

(Reporting By Dan Levine; Editing by Gary Hill, Matthew Lewis and Phil Berlowitz)

• A Permanent Economic Emergency