https://github.com/jhy/jsoup/issues/296

Notice that I didn't change the definition of the original StringUtils.isWhiteSpace() as that was used for HTML parsing and other purpose. The change is applied to StringUtils.isBlank() only.

I made an additional change to rename the original isWhiteSpace to isHTMLWhiteSpace. I propose to make such change as there are two different usages of "whitespace" in the project.