[gblake]

On the down side, Java will run quite a bit slower.

This might be a distinction without a difference - Depending on the Java Virtual Machine you are using, Java Byte Code can run plenty fast for plenty of applications - This only becomes important if you are running out of clock cycles - And, for my 2 cents, if I start doing any work likely to exhaust the clock cycles of a microcontroller, I'm going to want to offload the microcontroller (attach a fast General Purpose computer (a co-processor) to do the intense math or other heavy lifting).

Find out what speed you (really) REQUIRE before using speed as a selection criterion.

The garbage collection causes hiccups where the OS is doing something besides running your code.

In full fledged Java implementations, you can invoke garbage collection as often as you want. This doesn't explicitly prevent the VM from deciding to run it; but it does give you a chance minimize how often the VM will surprise you by cleaning up after yourself.

C++ probably has more robotics usage, so more code to borrow from.

Yes and no - I suspect that if you look at the robot code as the core of a large collection of general purpose development and debug code, and environments, you might find that there are plenty of Java infrastructure tools that make it worth your while to use Java. It is that infrastructure that
chews up most of my time when developing robot-ish software; not the robot software itself.

Or you might not

Blake