Check the javadoc:
http://java.sun.com/j2se/1.5.0/docs/api/javax/swing/JPasswordField.html#getPassword()

Since in Java the strings are immutable, there is a chance that the
password will stick in the heap for a long time. Thus, it's considered
safer to use the array representation of the password to calculate a
hash and then zero out the array's contents.

If you are not that concerned with security, you can keep using the
getText() or convert the pass to String and use it as plain text.

Dimitar