The exceptions that can be thrown are split into user and system categories.
If your problem is related to the ORB, unless your application is doing nothing or giving you the wrong result, your log file or terminal is probably full of exceptions that include the words CORBA and rmi many times. All unusual behavior that occurs in a good application is highlighted by an exception. This principle also applies for the ORB with its CORBA exceptions. Similarly to Java™, CORBA divides its exceptions into user exceptions and system exceptions.
User exceptions are IDL defined and inherit from org.omg.CORBA.UserException. These exceptions are mapped to checked exceptions in Java; that is, if a remote method raises one of them, the application that called that method must catch the exception. User exceptions are usually not unrecoverable exceptions and should always be handled by the application. Therefore, if you get one of these user exceptions, you know where the problem is, because the application developer had to make allowance for such an exception to occur. In most of these cases, the ORB is not the source of the problem.
System exceptions are thrown transparently to the application and represent an unusual condition in which the ORB cannot recover gracefully, such as when a connection is dropped. The CORBA 2.6 specification defines 31 system exceptions and their mapping to Java. They all belong to the org.omg.CORBA package. The CORBA specification defines the meaning of these exceptions and describes the conditions in which they are thrown.
- BAD_OPERATION: This exception is thrown when an object reference denotes an existing object, but the object does not support the operation that was called.
- BAD_PARAM: This exception is thrown when a parameter that is passed to a call is out of range or otherwise considered not valid. An ORB might raise this exception if null values or null pointers are passed to an operation.
- COMM_FAILURE: This exception is raised if communication is lost while an operation is in progress, after the request was sent by the client, but before the reply from the server has been returned to the client.
- DATA_CONVERSION: This exception is raised if an ORB cannot convert the marshaled representation of data into its native representation, or cannot convert the native representation of data into its marshaled representation. For example, this exception can be raised if wide character codeset conversion fails, or if an ORB cannot convert floating point values between different representations.
- MARSHAL: This exception indicates that the request or reply from the network is structurally not valid. This error typically indicates a bug in either the client-side or server-side run time. For example, if a reply from the server indicates that the message contains 1000 bytes, but the actual message is shorter or longer than 1000 bytes, the ORB raises this exception.
- NO_IMPLEMENT: This exception indicates that although the operation that was called exists (it has an IDL definition), no implementation exists for that operation.
- UNKNOWN: This exception is raised if an implementation throws a non-CORBA exception, such as an exception that is specific to the implementation's programming language. It is also raised if the server returns a system exception that is unknown to the client. If the server uses a later version of CORBA than the version that the client is using, and new system exceptions have been added to the later version this exception can happen.