Is there anything simple Java can't do that can be done in a similar language or vice versa?

Lets say you have a piece of software in language X and you rewrite it entirely to Java (or the other way around), what are the little things that would seriously hamper the translation?

At first I was thinking of comprehensions or multiple exit loops, but these are easily rewritten with a for_each loop with an if statement and a local variable respectively.

Maybe Exceptions? But which language does not have a similar construct?
Polymorphism? But I don't see how I could show that in a few lines.

I'm looking for a short and sweet example, that would give some serious headache to work around.