What's in a name? Or how to validate a name field in Java.

Today I had to check a customer name input field for validity. And it is hard, very hard! The first thing that popped to mind was this brillant blog post on assumptions we make about names. The article lists 40 common assumptions about names and all of these are false, one of which is that people have a name. However, it would be nice to have some info about the customer, so I do assume that customers have at least a first and last name. The simplest approach would be a regex that checks for upper/lower case letters:
/** too simple, alfabet + white space only */
private boolean isValidNameNaive(String name) {
    return name.matches("[a-zA-Z\\s]+");
}
However, this may cover your name, your mom's and that of two of your best friends, but that's about it. International names such as 張三李四, Путин or Beyoncé won't pass. This is where the unicode letter catcher steps in: \p{L}. We also wouldn't want to leave out Ed O'Neill or any Husband Name-Maiden Name, so let's add '-,. to the mix just to be sure. This turns into:
/** better, unicode and some common non-letter-characters */
private boolean isValidName(String name) {
    return name.matches("[\\p{L}'\\-,.\\s]+");
}
And will match quite a lot of the names out there (first, last and prefixes) without leaving too much room for exploitation or otherwise unwanted content. Still not enough to cover every name out there, but good enough for some cases, such as mine.