It seems Java developers are very disappointed by the fact that not only does Leopard not ship with Java 1.6 but that the Java 1.6 preview available from the Apple Developer Connection is simply gone.
Does that mean that Java applications will stop working on Leopard ? No.
Leopard comes with Java 1.5. Quote from Apple: "Mac OS X includes the full version of J2SE 1.5, pre-installed with the Java Development Kit (JDK) and the HotSpot virtual machine (VM), so you don't have to download, install, or configure anything."
So, you can still run OmegaT, OpenLanguageTools, Heartsome's Translation Suite and any other software that does not depend on Java 1.6 without a glitch, as far as I've tested.
Some developers have reported that the Java 1.6 preview totally broke Java on Leopard but it is not the case for me... [see the update at the bottom]
Anyway, it is likely that Java 1.6 will be released soon as seems to believe Eric Burke of "It's just a bunch of Stuff That Happens"...
Check this Apple Developer Connection page to see if you miss a Java 1.5 update on Tiger.
ps1: OpenLanguageTools is not advertised as a Mac application but the UNIX version runs very well on Mac.
ps2: Heartsome will soon release version 7 of its suite.
update: Java 1.6 did indeed break a few things. When Leopard is installed the Java preferences in /Applications/Utilities/Java allow you to change the default JVM to Java 1.6. Don't do that! If you do, a number of processes that are meant to run with an unspecified version of Java will try to run with Java 1.6 and won't work. Since the Java Preferences also seems to call that unspecified version of Java, you will be stuck without being able to get back to a default Java 1.5.
Well, there may be tricks to do get back there quickly, be the safest route seems definitely to remove Java 1.6. Javablog indicates a straightforward procedure to do so. Not for the faint of heart! But that is the cost of using developer preview beta software...