tck test suite isn't release for apache. the only official oopen source is OpenJDK. Any spec to the language is run through a consortium of companies but is rigged heavily in Oracle's favor. The whole drama and fall out of Apache Harmony (?) sort show this. Plus Sun microsystem promise Apache the TCK test but never delivered. So sun and oracle rule Java with an iron fist.

How many people actually run a different JVM, though? Market share is really unbalanced, which is unhealthy but due to the stranglehold on official compatibility certification which is the hallmark of a one vendor world.