P.S.: I'm using JavaFX 2.2.
Basically, javaFx has the issue which is coupled with CORS - https://javafx-jira.kenai.com/browse/RT-35868. Assuming that web services which you are using, have CORS enabled you can try the following approach:
java -Dsun.net.http.allowRestrictedHeaders=true <your main class here>
Hope it will help you