Software firm Oracle has dragged Google to court over a copyright and patent infringement of its Java software.

The US software giant claimed that Google infringed as many as seven patents that came under its direct control after it purchased Sun Microsystems in January.

Oracle said that Google's mobile phone operating system uses elements of its technology. The software giant accused the search giant for knowingly and repeatedly infringing its Java-related intellectual property and incorporating Java code into Android operating system.

The lawsuit followed a research carried out by the Gartner revealing that worldwide sales of Android phones have outshined Apple's iPhone for the first time.

Speaking on the issue, Google said, "We will strongly defend open-source standards and will continue to work with the industry to develop the Android platform."

Such lawsuits will not only a trouble for Google but also for partners such as HTC who make use of Android operating system.

Google’s Android that has become the top smartphone platform in the US was launched in 2007. Google has built up a formidable array of patents in search, but it may not have a deep portfolio of mobile patents to counter lawsuits from rivals.