#vulnerable code 
                                protected void assertSuccessfulAuthentication(String providerId) {
        this.driver.navigate().to("http://localhost:8081/test-app/");

        assertTrue(this.driver.getCurrentUrl().startsWith("http://localhost:8081/auth/realms/realm-with-broker/protocol/openid-connect/login"));

        // choose the identity provider
        this.loginPage.clickSocial(providerId);

        assertTrue(this.driver.getCurrentUrl().startsWith("http://localhost:8082/auth/realms/realm-with-saml-identity-provider/protocol/saml"));

        // log in to identity provider
        this.loginPage.login("saml.user", "password");

        assertTrue(this.driver.getCurrentUrl().startsWith("http://localhost:8081/auth/broker/realm-with-broker/" + providerId));

        // update profile
        this.updateProfilePage.assertCurrent();

        String userEmail = "new@email.com";
        String userFirstName = "New first";
        String userLastName = "New last";

        this.updateProfilePage.update(userFirstName, userLastName, userEmail);

        // authenticated and redirected to app
        assertTrue(this.driver.getCurrentUrl().startsWith("http://localhost:8081/test-app/"));

        KeycloakSession samlServerSession = brokerServerRule.startSession();
        RealmModel brokerRealm = samlServerSession.realms().getRealm("realm-with-broker");

        UserModel federatedUser = samlServerSession.users().getUserByEmail(userEmail, brokerRealm);

        // user created
        assertNotNull(federatedUser);
        assertEquals(userFirstName, federatedUser.getFirstName());
        assertEquals(userLastName, federatedUser.getLastName());

        driver.navigate().to("http://localhost:8081/test-app/logout");
        driver.navigate().to("http://localhost:8081/test-app/");

        assertTrue(this.driver.getCurrentUrl().startsWith("http://localhost:8081/auth/realms/realm-with-broker/protocol/openid-connect/login"));

        // choose the identity provider
        this.loginPage.clickSocial(providerId);

        // already authenticated in saml idp and redirected to app
        assertTrue(this.driver.getCurrentUrl().startsWith("http://localhost:8081/test-app/"));
    } 
                            #location 35 
                            #vulnerability type NULL_DEREFERENCE
#fixed code
                                protected void assertSuccessfulAuthentication(String providerId) {
        this.driver.navigate().to("http://localhost:8081/test-app/");

        assertTrue(this.driver.getCurrentUrl().startsWith("http://localhost:8081/auth/realms/realm-with-broker/protocol/openid-connect/login"));

        // choose the identity provider
        this.loginPage.clickSocial(providerId);

        assertTrue(this.driver.getCurrentUrl().startsWith("http://localhost:8082/auth/"));

        // log in to identity provider
        this.loginPage.login("test-user", "password");

        doAfterProviderAuthentication(providerId);

        doUpdateProfile(providerId);

        // authenticated and redirected to app
        assertTrue(this.driver.getCurrentUrl().startsWith("http://localhost:8081/test-app/"));
        assertNotNull(retrieveSessionStatus());

        doAssertFederatedUser(providerId);

        driver.navigate().to("http://localhost:8081/test-app/logout");
        driver.navigate().to("http://localhost:8081/test-app/");

        assertTrue(this.driver.getCurrentUrl().startsWith("http://localhost:8081/auth/realms/realm-with-broker/protocol/openid-connect/login"));
    }