I think this will cause a lot people to move away from java and ultimately harm Oracle most, causing other companies to not follow their example.
Let's just stay away from java, there are plenty of free languages.
Java is as much an Oracle product, as water is an Aquafina product or space is a NASA product. So, no, Java has gained enough ubiquity and popularity now so that no one company can monopolize it.
Many open source implementations of Java already exist like Apache Harmony project, the OpenJDK or Red Hat's Iced Tea apart from Oracle's reference implementation.
Coming to the point of there being plenty of languages, I don't think there are any exact substitutes. Low level languages like C/C++ are a bit overkill for application development.
Python is good (I'm a big fan myself), but an interpreter is much slower than a JIT compiled language even on a quad-core. I think we should have python as an option, but that should not be the only language.
The only real replacement (and even a better one) in my opinion is C#. C# is a much evolved language than Java and is also open source (Microsoft has made it so through the MCP).