[mikece]

More than anything else: be honest and be yourself.

Emphasize your knowledge of programming, the cool things you've achieved in C++, Go, Ruby, and Python, that you might be rusty on the syntax of Java but it's not a foreign concept and can be productive almost from day one.

And maybe do some Java practice in the mean time? Maybe build something like a tinyurl clone in Spring (Boot) and post it to Github as "refreshing my Java skills" projects.