public static AccessTokenValidator create(Map<String, ?> configs) {
        return create(configs, (String) null);
    }
@Test
    public void testConfigureThrowsExceptionOnAccessTokenValidatorClose() {
        OAuthBearerLoginCallbackHandler handler = new OAuthBearerLoginCallbackHandler();
        AccessTokenRetriever accessTokenRetriever = new AccessTokenRetriever() {
            @Override
            public void close() throws IOException {
                throw new IOException("My close had an error!");
            }
            @Override
            public String retrieve() {
                return "dummy";
            }
        };

        Map<String, ?> configs = getSaslConfigs();
        AccessTokenValidator accessTokenValidator = AccessTokenValidatorFactory.create(configs);
        handler.init(accessTokenRetriever, accessTokenValidator);

        // Basically asserting this doesn't throw an exception :(
        handler.close();
    }