[LeelandS]

As a student who was on a team who cycled through 3 different programming languages over a few seasons, I may be able to offer a little insight, especially on switching to Java.

First of all, if you're comfortable with Java, use Java. If you feel that, after evaluating Java for FRC purposes, then you have two options:
-Learn C++. It's somewhat similar to Java, albeit some key differences. More or less, if you can program in Java, learning C++ will be less of a challenge. That's from personal experience. I haven't looked, but I've also been told several times (by mentors trying to get us back to C++) that C++ is also much more supported for FRC. So that's an option.
-Look at your previous year's Labview code. Try to learn it, make sense of it, etc. I don't know how documentation in Labview works, but if it is properly documented, that should be quite a learning experience. If it's not properly documented... that could be quite a task.

Now, if you decide you'd like to stick with Java, there are another few things I can suggest:
-Look for teams who have posted Java code online. If nothing else, you should be able to better understand how Java works in terms of FRC.
-Practice by converting your old Labview code to Java. 1126 did that in 2010 I believe, converting our 09' bot (Labview) to Java. That has long since passed, with the dismantling of the 09' bot, but it could be a great experience for you and anyone you do it with.
-Make sure you know the basics of Java in general FIRST. That'll make things go over a little smoothly. That's just a general rule, though.

I hope these help. The most basic thing I can suggest is think your decision through. Look over all the basis you have, consider all your option.