Java version is working fine now.

BTW Google kind of think just like you do: https://github.com/google/auto/blob/master/value/userguide/builders.md

Instantiate a builder to instantiate a class every time you want to instantiate a class doesn't seem to be a big gain, please check mor on the topin at this SO answer: https://stackoverflow.com/questions/5007355/builder-pattern-in-effective-java

When you ask for something post a question, not an issue.
See the top of the page: 284 guys passed the Java kata.
It appears that your code is too slow.