SAN FRANCISCO (MarketWatch) -- Oracle Corp. filed a lawsuit against Google Inc. on Thursday, alleging that the Internet search giant has infringed on intellectual property related to the Java software that Oracle acquired when it purchased Sun Microsystems Inc.

Oracle ORCL, +0.38% filed a complaint in federal court in California, alleging the infringement of seven patents and copyrights by Google's GOOG, +0.01% Android mobile operating system software.

"Google has been aware of Sun's patent portfolio, including the patents at issue, since the middle of this decade, when Google hired certain former Sun Java engineers," Oracle said in its complaint, adding that Android developers have been making unlicensed use of Java copyrights.

A Google spokesman said the company hasn't yet been served with the lawsuit, and is therefore unable to comment.

An Oracle spokeswoman declined to comment.

Oracle obtained Java as part of its $5.6 billion purchase of Sun, which closed earlier this year following a lengthy antitrust review in Europe.

"Java is the single most important software we've ever acquired," Oracle Chief Executive Larry Ellison said during a conference call when the acquisition was announced, early last year.

Oracle reiterated that sentiment in its lawsuit. "One of the most important technologies Oracle acquired with Sun was the Java platform," the company said in its complaint, adding that the Java platform has now attracted over 6.5 million software developers.

"Google's Android competes with Oracle America's Java as an operating system software platform for cellular telephones and other mobile devices," Oracle said in its complaint, while noting that the Android system includes Java applications.

Java was publicly introduced by Sun -- at one time a Silicon Valley software and hardware powerhouse -- in the 1990s. Sun later released much of Java's inner workings to outside developers under an open-source license in 2006, in hopes of boosting its development.

Java is used in a number of ways, in addition to deployment in mobile phones.

Google's Android, meanwhile, has made significant progress since the company unveiled its own open-source software initiative in 2007.

According to data published Thursday by Gartner Inc., Android's share of the smart-phone market surged from 1.8% in the second quarter of last year, to 17.2% in the same period this year -- overtaking Apple Inc.'s AAPL, +1.50% iPhone operating system, and placing Google third behind Symbian and Research In Motion Ltd. RIMM.

Oracle asks in its complaint for unspecified damages, and that any software found to be in violation of Oracle's copyrights "be impounded and destroyed."

Key Google partners providing phones that run on Android include Motorola Inc. MOT and HTC Corp.

A Motorola spokeswoman did not immediately respond to a request for comment.