src/main/java/com/authlete/jaxrs/api/AuthleteApiImpl.java
@Override
    public String[] getRequestableScopes(long clientId) throws AuthleteApiException
    {
        // Call the API.
        RequestableScopes response = executeApiCall(
                new ServiceGetApiCaller<RequestableScopes>(
                        RequestableScopes.class, REQUESTABLE_SCOPES_GET_API_PATH, clientId));

        if (response != null)
        {
            // Extract 'requestableScopes' from the response.
            return response.getRequestableScopes();
        }
        else
        {
            return null;
        }
    }
@Override
    public String[] getRequestableScopes(long clientId) throws AuthleteApiException
    {
        // Call the API.
        RequestableScopes response = executeApiCall(
                new ServiceGetApiCaller<RequestableScopes>(
                        RequestableScopes.class, REQUESTABLE_SCOPES_GET_API_PATH, clientId));

        if (response != null)
        {
            // Extract 'requestableScopes' from the response.
            return response.getRequestableScopes();
        }
        else
        {
            return null;
        }
    }
Call <code>/api/client/extension/requestable_scopes/get/<i>{clientId}</i></code> API.