public static List<String> getClientIdentities(X509Certificate x509Certificate) {
        
        List<String> names = new ArrayList<>();
        for (CertificateIdentityMapping mapping : clientCertMapping) {
            List<String> identities = mapping.mapIdentity(x509Certificate);
            Log.debug("CertificateManager: " + mapping.name() + " returned " + identities.toString());
            if (!identities.isEmpty()) {
                names.addAll(identities);
                break;
            }
        }

        return names;
    }
Returns the identities of the remote client as defined in the specified certificate. The
identities are mapped by the classes in the "provider.clientCertIdentityMap.classList" property. 
By default, the subjectDN of the certificate is used.

@param x509Certificate the certificate the holds the identities of the remote server.
@return the identities of the remote client as defined in the specified certificate.
xmppserver/src/main/java/org/jivesoftware/util/CertificateManager.java