Eric Schmidt, the CEO of Google, was formerly a chief technical officer for Sun Microsystems. Sun Microsystems was bought by Oracle.
The move is interesting because when Sun Microsystems was a separate entity it promoted Java as an open source option.
Google never formally took out a licence from Sun Microsystems, while Java is widely used in a large number of applications created by other vendors. The law suit will cause other manufacturers to wonder whether Oracle will start a patent hunt against them.