Google Inc. (GOOG) has a way of pulling rabbits out of a hat when it comes to defending itself from seemingly impending legal demise.  Not long ago it defeated cable giant Viacom, Inc. (VNV) in a $1B USD court battle, when it proved that Viacom employees had secretly uploaded files to YouTube to try to frame it in infringement. 

Now, a bombshell piece of evidence has just been delivered in the company's $2.6B USD court battle with Oracle Corp. (ORCL), which threatens to be equally damaging to the rival software makers' intellectual property infringement claims.

I. Sun CEO: "Pleased" to Welcome Android to the Java Family

Oracle's guiding premise in its lawsuit against Google is that Google infringed upon Java patents, which it obtained when it purchased Sun Microsystems in January 2010.  Just days ago, a judge ruled that Google appeared "brazen" in its alleged infringement based on email evidence Oracle presented.

Now a lost internet treasure has surfaced that promises to cast those emails in a whole new light.  Legal site Groklaw has unearthed a Sun Microsystems blog dating back to 2007 that offers an explosive revelation -- Sun appears to have verbally endorsed Google's use of mobile Java in Android.

In the blog former Sun CEO Jonathan Schwartz writes:

I just wanted to add my voice to the chorus of others from Sun in offering my heartfelt congratulations to Google on the announcement of their new Java/Linux platform, Android.  Congratulations!

I'd also like Sun to be the first platform software company to commit to a complete developer environment around the platform, as we throw Sun's NetBeans developer platform for mobile devices behind the effort. We've obviously done a ton of work to support developers on all Java based platforms, and were pleased to add Google's Android to the list.

And needless to say, Google and the Open Handset Alliance just strapped another set of rockets to the community's momentum - and to the vision defining opportunity across our (and other) planets.

Today is an incredible day for the open source community, and a massive endorsement of two of the industry's most prolific free software communities, Java and Linux.

That warm, glowing message stands in sharp contrast to Oracle's claims that Sun forbid Google from using the Apache distribution of Java, which formally hadn't passed the testing (and fees) required to gain a full license to Java's intellectual property.

Coincidentally, Oracle appears to have conveniently deleted the blog from Sun's web servers.  But unfortunately for Oracle, it lived on in web history caches.

II. A Growing Picture: Oracle Double-Crossed Google

A compelling case is emerging for so-called "reliance based estoppel".  Here's how this works.  If one company says something to another (say that they aren't going to enforce a particular piece of intellectual property) -- and then they turn around and sue that company after they relied on their advice, that is sufficient to typically drop the case if the accused can prove it was relying on the plaintiff's advice.

In this case Google is building a strong case to prove that it relied on Sun's assurances that it would not litigate with regards to the use of Java.  Mr. Schwartz has already given a sworn deposition that he publicly stated that Android was a "pair of rockets strapped to Java that will take our Java-community even higher."

The newly found blog paints an even clearer picture that Sun endorsed Google's use of Java -- something Oracle refutes.

First, a bit of clarification is necessary.  PC Java is totally open source under the Gnu Public License (GPL).  You can modify it; you can use it in commercial products; you can do virtually whatever you want with it.  Mobile Java implementations are covered under a different licensing scheme, though -- and are not freely commercially available.  This is why the Apache version that Google used in Android technically may have been in violation of Sun's intellectual property rights.

However, that's a moot point if Sun verbally permitted Google to use it.  After all, intellectual property rights are only as binding as the company's desire to enforce it.

Oracle will likely try to bar this evidence from court.   Presiding U.S. District Court Judge William Alsup is already chastising Oracle for trying to block evidence.  He wrote, "The big companies do not own the U.S. District Court, When it comes to a public hearing I’m not going to resort to Morse code to figure out what you are saying This is not a wholly-owned subsidiary of Oracle. Nobody is going to put my word under seal even if I refer to your secret documents."

Ultimately, any damages awarded will likely come from a jury trial.  Oracle will likely have a tough time proving that Google committed "unauthorized" infringement and owes it billions in damages -- when the original IP owner Sun was glowingly promoting Google's use just years earlier.

If it can't exclude the evidence, Oracle will likely argue either than Mr. Schwartz wasn't speaking on behalf of Sun (a hard sell given that it was on a corporate blog) or that Sun wasn't fully aware of the extent of Google's enforcement (again, hard to believe, plus it would be unclear if this would help nullify the estoppel).

Oracle's most compelling piece of evidence -- Android chief Andy Rubin's 2005 email:

If Sun doesn't want to work with us, we have two options: 1) Abandon our work and adopt MSFT CLR VM and C# language - or - 2) Do Java anyway and defend our decision, perhaps making enemies along the way

Now that evidence appears pretty weak as it is cast in speculative light -- not an actual plan of infringement.  In the end Sun did want to work with Google, so it appears to have been led to believe it didn't have to make that choice.

III. What's Left?

The real question is -- what happens next?  Even if Google defeats Oracle, that doesn't mean that it can use Java forever.  In fact, now that Oracle has expressly forbidden it, even if it wins the case it still may be forced to modify its operating system or seek a license from Oracle.  In that regard Oracle may lose -- but still win.

The case stands as a warning to the open source movement.  Oracle came in all smiles and promises, but once it had sealed the acquisition deal, CEO Larry Ellison appears to have delighted in getting his hands dirty turning the open source movement's own intellectual property against it.

Now that property is in the hands of Oracle.  Of course the expiration for most U.S. patents is 20 years -- so Google will eventually be free of Oracle.  In the meantime, expect it to continue to fight Oracle's rights to this IP and fight for copyright reform.

Google's handset partners are currently facing similar licensing pressure [1][2] from Microsoft Corp. (MSFT), albeit without the lawsuit.  They also face multiple lawsuits from gadget-maker Apple, Inc. (AAPL) who has attacked the world's top three Android manufacturers [1][2][3][4][5], but has thus far avoided going after Google directly. 

Perhaps that's an inevitable reality for the world's biggest smart phone maker and arguably the world's most successful open source project.