In August 2010, Oracle sued Google citing patent and copyright infringement over the use of Java in Android. The suit alleged that Android, Android SDK and the Dalvik cache violated seven patents and contained copies of the original java code.
According to Oracle, Google used part of the Apache Harmony Java implementation in Android without a license to java patents and copyrights
In January 2011, Florian Muller (of Foss Patents) published an article claiming that Google copied 37 files directly from Java without license. But it later emerged that they were likely test files. Still, from a legal angle, it increased the risk on Google.
In June 2011, Google filed a document stating that Oracle wanted between US$1.4 and US$6.1 billion as settlement charges. It later appeared that Oracle wanted US$2.6 billion.
Later in the same month, USPTO rejected 17 of 21 claims in one of the patents, though 4 of the claims remained along with 118 contained in the other 6 patents which were not contested.
In July 2011, Judge asked Oracle to rethink about the US$2.6 billion value and suggested a starting point of ~US$100 million.
Oracle narrowed it down to US$2 billion but in January 2012 the judge refused to proceed with the trial asking Oracle to file more appropriate claim value.
At this time, Oracle wanted to separate the patent claims from copyright to accelerate the case, but the judge declined the request
Later in February, Oracle dropped the patent of which 17 of the 21 claims where earlier reject by USPTO.
Oracle is interested in an early start to the case claiming that delay of every day is harming Oracle irreparably by diverting the Java developer ecosystem to Android.
Oracle has now again stated that it wants the trial to start in mid-April and hence could withdraw 3 of the remaining 5 patents (2 have already been withdrawn). The remaining 2 include patent 520 and RE104 - the Gosling patent, which will expire in December.
Oracle though do put in a caveat that only the rejected claims of the patent will be withdrawn and if the claims on the other patents are accepted than they will come back into play.
Based on Oracle's interest for a quick trial and the judge's insistence on conducting both the patent and the copyright trials simultaneously, Oracle might have to make further concessions.
Any further concession will further hit Oracle in the case, and it might eventually end up becoming a copyright case or even a 1 patent case, severely undercutting Oracle's initial assertion of massive infringement by Oracle.
At this stage it appears that the liability on Google could be severely limited, even Oracle manages to win, as the case is turning into a copyright infringement rather than a patent cum copyright infringement case.
Source: Foss Patents
Source: Foss Patents