Why is JavaFX documentation different from Java 8 documentation?

I recently learned that Java FX2 is replacing Swing for GUI development in Java. I tried to check this in the API documentation and couldn't find javafx

one listed as javax.swing

. I found that the documentation for JavaFX was created, but separate from the Java 8 docs.

My question is, why would Oracle do this? Is there something about the API structure that I don't understand?