StringUtils.isBlank does not work correctly with strings containing non-breakable whitespace characters

isBlank uses java.lang.Character.isWhitespace(char ch) method, which has not been changed for a long time for backward compatibility. Over the years non-breakable whitespaces were introduced and are now used in some cases. So if we execute the code

org.apache.commons.lang.StringUtils.isBlank("\u00A0"); //returns false
org.apache.commons.lang.StringUtils.isBlank("\u202F"); //returns false
org.apache.commons.lang.StringUtils.isBlank("\u2007"); //returns false

we will get 3 falses, which is not right, according to StringUtils.isBlank documentation:

Checks if a String is whitespace, empty ("") or null.

I suggest fixing it by using regex pattern

"^[\\p{Z}]*$"

instead of looping over the string characters. I know that it is a bit less fast than it works now, but it will work much more correctly. I would be glad to do it myself and write unit tests for it, so if you want, please contact me via email alex.bohush@gmail.com

Additionally, I would modify the documentation itself too, because it does not tell that it returns true when meeting multiple whitespaces.