I just went to download JDK 1.5 for an installation of JetSpeed2, and was surprised that it wasn't immediately there at Suns site.
I don't think you'll see an SCJA exam on Java 6 for quite a while. SCJA is realy more concerned with high level Java concepts, as opposed to the intricate details about how the various different versions work. Master the high level stuff, and the basics of Java syntax, such as looping, initiaization, and conditional statements, and you really shouldn't have to worry about the differing versions.
I’ve looked at a lot of different solutions, and in my humble opinion Aspose is the way to go. Here’s the link: http://aspose.com