}
@Override
public boolean login() throws LoginException {
if (callbackHandler != null) {
CredentialsCallback ccb = new CredentialsCallback();
try {
callbackHandler.handle(new Callback[] {ccb});
Credentials credentials = ccb.getCredentials();
if (credentials == null) {
Set<Credentials> sharedCredentials;
Object sharedObj = sharedState.get(LoginModuleImpl.SHARED_KEY_CREDENTIALS);
if (sharedObj == null || !(sharedObj instanceof Set)) {
sharedCredentials = new HashSet<Credentials>();