Replace StringHelper#join by Java's String#join
When I was writing the patch for and reviewed some portion of the code, I noticed the StringHelper and StringUtil classes. Then after quickly reading it, I added a post-it to my monitor with a note that at least the #join method from StringHelper could be replaced by the String#join from Java 1.8.
As I had some spare time this weekend decided to submit the patch. Though, I'd be fine if others prefer not to touch the code, in case it's considered too risky. Just wanted to remove the post-it from my monitor
Ubuntu LTS, Oracle Java 8