private PrincipalProvider getPrincipalProvider() {
PrincipalProvider principalProvider = null;
if (callbackHandler != null) {
try {
PrincipalProviderCallback principalCallBack = new PrincipalProviderCallback();
callbackHandler.handle(new Callback[] {principalCallBack});
principalProvider = principalCallBack.getPrincipalProvider();
} catch (IOException e) {
log.warn(e.getMessage());
} catch (UnsupportedCallbackException e) {
log.warn(e.getMessage());
}