Our university adopted it right away and made it in 1997 the official language for compiler development and distributed systems classes.
Without bothering to search the Internet, NIO was either introduced in 1.4 or 1.5.
Yes they have open specifications, but they also have trademarks and compliance certifications.
The JDK was open source, but the license prevented its use for mobile devices without a Sun approved license, that Google didn't want to pay for.
So now Google has actually created a fork in the Java community.
Just imagine when you have Java 9 with modules, or Java 10 with reiffied generics, value types, JNI replacement, official unsafe package, among many other roadmap features, how to keep the code portable between Android Java and the real Java.
edit: The article does state at the end that google will still modify OpenJDK for their own needs, but that still means that the vast majority of the implementation will be the same, so this seems to avoid most incompatibility issues.
I know Redhat is one of the other major OpenJDK contributors, and a lot of distributions are relying on IcedTea. It will be interesting to see how this develops.
Java is definitely still really popular for development overall (TIOBE 2015 #1). My personal concern with Oracle vs. Google though is that Oracle does not own the language, and the copyright claim on APIs seems pretty aggressive. The JVM and Java have open specifications which in theory anyone should be allowed to implement (practice is admittedly a bit different). Even the official JDK was open source, which Oracle seems a bit hostile toward considering what they've done with purchases like MySQL and how the community largely responded.
Claiming copyright on an API seems somewhat akin to Keurig 2.0. Although, I think courts are having trouble keeping pace with technology.