Returns all principals associated with the corresponding Subject. Each principal is an identifying piece of
information useful to the application such as a username, or user id, a given name, etc - anything useful
to the application to identify the current <code>Subject</code>.
<p/>
The returned PrincipalCollection should <em>not</em> contain any credentials used to verify principals, such
as passwords, private keys, etc. Those should be instead returned by {@link #getCredentials() getCredentials()}.
@return all principals associated with the corresponding Subject.
Returns all principals associated with the corresponding Subject. Each principal is an identifying piece of information useful to the application such as a username, or user id, a given name, etc - anything useful to the application to identify the current <code>Subject</code>. <p/> The returned PrincipalCollection should <em>not</em> contain any credentials used to verify principals, such as passwords, private keys, etc. Those should be instead returned by {@link #getCredentials() getCredentials()}.
@return all principals associated with the corresponding Subject.