In my opinion, C++ is awesome because it makes you be a better coder. It won't hold your hand like Java and it will never tell you you can't do something. Want to create entirely new code that does wacky things? Go for it, but make sure you write it properly or the compiler and your OS will drain the kiddie-pool when you run off the end of memory.
Sure Java is 100% portable thanks to its interpreters, but it's also horrible and slow because it has to interpret everything line by line. C++ compiles down to one small, lightweight executable. Sure it's different on every system and compiling takes a long time, but at runtime you actually get stuff done this week.
What I'm saying is that I'm glad Xenonauts uses C++ for its heavy lifting instead of Java (looking at you, Project Zomboid).