Its will be a little saying too much, to say node.js revolutionized paypal. But speaking as a matter of fact programming languages do play significant role in the overall productivity of the teams.

I wouldn't be too surprised if they are saying using Java was making it difficult to turnaround issues. The problem isn't Java the language itself, but the processes involved in taking changes to production with these languages are generally so much ceremony large turnaround times become the norm.

Add to this issues like fixing build failures, test failures, code reviews that span meta aspects of code(config changes, xmls etc), running around to get libraries standardized per your company standards(getting it into your local maven repo etc); and much more. These sort of things really slow you down. With these if you are tending to multiples issues, or if you have dependencies on your colleagues- I wouldn't be surprised with the 6-month delays mentioned in the article are actually true.