Java Security

Hi,
I need to encrypt a file in Java using AES, given an 'EncryptionKey'. The "EncryptionKey" will be given to me as a String. Later, the client needs to be able to decrypt it using the same "EncryptionKey", with ANY decryption tool.

I'm not sure how this can be done. The sample codes I saw online usually use a KeyGenerator to generate the Key. It seems like maybe I can use the "EncryptionKey" as a password, and use this password to generate a Key like this:
http://javaalmanac.com/egs/javax.crypto/PassKey.html
However, the link above uses DES. If I want to use AES, is it possible? Also, the client is not supposed to know anything about the salt and iteration count, all he knows is the "EncryptionKey".

Thanks a lot!