I think the problem is testing. If you use a tool to convert one language to
another, you have to check that the result works, which involves a lot of
testing, possibly as much as you had to do to get the original working in the
first place. So it's expensive.
It will usually be cheaper to
Java has vast number of libraries.
Good thing is Golang is catching up with its own style.
There are cases though where there is no equivalent libraries ( PDF reading
/ writing, TIFF reading writing, Office File formats)
There were a few attempts for Java to Go conversions but not complete
