regex - Remove all non-"word characters" from a String in Java, leaving accented characters?

Question

Apparently Java's Regex flavor counts Umlauts and other special characters as non-"word characters" when I use Regex.

        "TESTüTEST".replaceAll( "\W", "" )

returns "TESTTEST" for me. What I want is for only all truly non-"word characters" to be removed. Any way to do this without having something along the lines of

         "[^A-Za-z0-9??ü??ü?éèáàúùóò]"

only to realize I forgot ??

Answer 1

Use [^p{L}p{Nd}]+ - this matches all (Unicode) characters that are neither letters nor (decimal) digits.

In Java:

String resultString = subjectString.replaceAll("[^\p{L}\p{Nd}]+", "");

Edit:

I changed p{N} to p{Nd} because the former also matches some number symbols like ?; the latter doesn't. See it on regex101.com.