Depending on how it's used in the Java code, it might be fine to replace it with an empty string.

He knows it, that's why he mentions lack of null (nil) in Strings in Go as an issue when porting the code.

But depending on how the Java client uses null, "" can do just as well. It's not like you have many other options (except to add your own composite struct on top of String, or to use a guard value that's still a string).

I hate that everything has 5o be checked against null in Java. It sucks a lot