W opisie GAE (https://developers.google.com/appengine/docs/whatisgoogleappengine) znalazłem taką informację:
Applications cannot write to the file system in any of the runtime environments. An application can read files, but only files uploaded with the application code.
...
The environment includes the Java SE Runtime Environment (JRE) 6 platform and libraries. The restrictions of the sandbox environment are implemented in the JVM. An app can use any JVM bytecode or library feature, as long as it does not exceed the sandbox restrictions. For instance, bytecode that attempts to open a socket or write to a file will throw a runtime exception.
Czy to oznacza, że przykładowo nie będę mógł stworzyć servletu który będzie uploadować plik z komputera użytkownika na serwer?