A recent discussion on our users forum  has surfaced (again) the need to encrypt the password fields in the persistence.xml. In the particular scenario outlined in the posting, this user wanted to encrypt the password sent into Apache DBCP via the url string. In my mind, that's a separate problem related to DBCP.
But, OpenJPA has openjpa.Connection*Password properties that could be encrypted. And, the new JPA 2 spec outlines a javax.persistence.jdbc.password property that would be nice to encrypt.
I'm opening this Issue as a Feature request, but it could also be considered a bug since a non-jndi environment is crippled from a security standpoint.