NetworkInterface not supported on GoogleAppEngine?

Question

It seems to me that Javas "NetworkInterface" isn't supported on GoogleAppEngine - not a surprise I guess given the limited Java .net support on GAE. I do however want to use the BSON Java library to covert my string to a BSON object (ObjectID). The problem is that it uses the below as part of the generation of the ObjectId:

StringBuilder sb = new StringBuilder();
Enumeration<NetworkInterface> e = NetworkInterface.getNetworkInterfaces();
while ( e.hasMoreElements() ){
    NetworkInterface ni = e.nextElement();
    sb.append( ni.toString() );
}
machinePiece = sb.toString().hashCode() << 16;

Which is clearly problematic when using GoogleAppEngine. Does anyone know an alternative to NetworkInterface that is supported by GAE that I could use in the above case?

It's really making me tear my hair out!

For reference the offending code appears between lines 356 and 362 in the below file: https://github.com/mongodb/mongo-java-driver/blob/2.11.x/src/main/org/bson/types/ObjectId.java

Answer 1

If you have to use mongoDB for your application, I recommend you to switch to managed vm.

Managed VM will allow you to have full access to all Java.

If you are still early in development, I would recommend that you see if you can datastore for your back-end. The biggest time saving of using a platform like GAE is auto scaling and auto maintenance of your application stack.

Answer 2

It depends what your goal is - if you want to create a hashcode based on the local (virtual) machine, as this code roughly seems to be doing, you can use com.google.appengine.api.utils.SystemProperty.instanceReplicaId or com.google.appengine.api.modules.ModulesService.getCurrentInstanceId() and get their hashcode.

If you really want to associate the hashcode with a unique combination of available network interfaces, you'll need to use another platform.