my solution would throw if both input streams were empty, while an empty stream could reasonably be expected in that case. this situation should either be explicitely ruled out, or tested for

needs a bump to newer Node versions

Interesting task!

(Note: generator functions as presented in this problem slightly diverge from generator functions in actual JS, but it's a little simpler this way.)

To me it's the opposite. I think this makes it more complex, because the first next call behaves differently from subsequent ones.

I really couldn't imagine that this Kata is that level of a pazzle. It seems like a hidden bonuce quest about the Java language understanding.
I dont think that all the responses were helpful, but thank you anyway for spending time to answer me. ... and yes, I got through. :)

Read the statements that you find

Well, the 1 semicolon limit includes the imports too

Now focus on this part

Well, the 1 semicolon limit includes the imports too

Now add the semicolons of the imports with those of your code

1 + 1

Notice that the result of the above expression is not in your favor

import java.util.stream.*;

Isn't that a semicolon?

you have TWO semicolons, please limit it to ONE.

we need at least one for the return expression.

That's why you get the 1 semicolon :P But that's it.

Can it be clarified? How can we write Java code without any semicolons? we need at least one for the return expression.

All non-lazy solutions are invalidated and no new have appeared in the meantime so issue seems sufficiently fixed.

This following code has only one semicolon ignoring the imports,

Well, the 1 semicolon limit includes the imports too. It's not really a kata issue.

Another one string solution ^^. Good choice.

Thank you. I have enjoyed solving this kata.