Java is already available if you're Jailbroken...
Tiny Innaworks has emerged as the temporary savior of a red-faced Sun Microsystems and thousands of developers itching to get their applications running to Apple's iPhone and Touch. Sun will use next month's JavaOne conference to demonstrate technology from mobile tools specialist Innaworks that converts Java Micro Edition code …
Jonathan Schwartz the day before Android SDK became available:
‘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.’
The Blog entry has now been edited:http://blogs.sun.com/jonathan/entry/congratulations_google
The Java implementation is a port of JamVM/GNU Classpath. It was first ported back in November last year :
Of course, it isn't "Java" as neither JamVM or GNU Classpath has passed Sun's TCK. But as Sun doesn't make this available to open-source projects it's hardly surprising.
Yes, Sun has announced a new licence for the TCK, but this applies only to implementations substantially derived from Sun's OpenJDK, which neither JamVM or GNU Classpath is.
OpenJDK Community TCK license:
Porting Java to the IPhone was done already, see http://blogs.sun.com/hinkmond/entry/houston_we_have_liftoff but of course it can't be released until they have a legal agreement