Pattern problem (capturing groups)

Hi all,

I am trying to match strings that consist of two identical vowels. This should be a super-easy task, but somehow it doesn't work. My regular expressoin is "([aeiou])\1".

The following statement returns false:

Pattern.matches("([aeiou])\1", "aa");

Can anyone help? It is my first time using capturing groups so I may be doing something wrong. However, the examples I read here seem to indicate I am doing it fine?

Thanks in advance.

EDIT: Oh nevermind, I just needed to escape the backslash... "([aeiou])\\1".