Oracle VM Manager is a multi-layered application. As such, checks on the legitimacy of operations are performed at various levels within the Oracle VM Manager Core. Some errors may be caught within the Web Services layer itself, while others may only be triggered by the Core rule evaluations. This should not make any difference within your application itself. An exception should be treated as such, regardless of where it originates from.

For instance, the following exception returned as a Job error for a web services request, is as much of an exception as a rule exception returned by Core:

ovm.mgr.ws.model.WsException: NETWORK_000008: Cannot perform operation Modify Role
List on a Server local Network: Modify Role List

Equally, a rule exception from within the core, is as important as an error generated at the Web Services layer:

com.oracle.ovm.mgr.api.exception.RuleException: OVMRU_002043E Cannot release
ownership of Repository: MyRepo. Virtual Disks/CDroms:
[0004fb0000120000eb8cd3defdc71ba5.img on 0004fb0000060000e3ea97cd6b8d45bd,
0004fb0000120000f2ba448c46f4fc12.img on 0004fb0000060000e3ea97cd6b8d45bd],
are still assigned to VMs/Templates that have configuration files in another
repository.

It is also worth noting that exceptions that are returned from the API may vary in terms of the error message or exception code that is returned depending on whether you are using the SOAP API or the REST API. If you are coding an application that can use either API, you need to ensure that your code is consistent in handling these exceptions regardless of the API used.