How to determine whether a character is a letter in Java?

Question

How do you check if a one-character String is a letter - including any letters with accents?

I had to work this out recently, so I\'ll answer it myself, after the re

Answer 1

Just checking if a letter is in A-Z because that doesn't include letters with accents or letters in other alphabets.

I found out that you can use the regular expression class for 'Unicode letter', or one of its case-sensitive variations:

string.matches("\\p{L}"); // Unicode letter
string.matches("\\p{Lu}"); // Unicode upper-case letter

You can also do this with Character class:

Character.isLetter(character);

but that is less convenient if you need to check more than one letter.