Are special characters in e-mail address possible?

Question

I'm using Apache Commons e-mail validator and it refuses to accept email address like:

ąźóęł@email.com

so I would like to ask if it's right to not allow them or I should change validator?

Answer 1

http://en.wikipedia.org/wiki/E-mail_address#RFC_specification contains all the info you need: a link to the official RFC specs, which characters are good, etc.