1. How Java/RMI compares with COM/DCOM and CORBA ©2001 by Sachin Sood
Is it your cup of coffee?
How Java/RMI compares with COM/DCOM and CORBA
©2001 by Sachin Sood

2. Contents
Comparisons
Pros/Cons of Java/RMI
Which is the best?

3. Object Oriented Middleware System Comparisons
CORBA
COM/DCOM
JAVA/RMI
Meta Object Model:
Uses IDL
Uses MIDL
No IDL used
Stub Generation:
IDL generates C/S stubs
MIDL generates C/S stubs
Compiler (rmic) generates C/S stubs
Location Transparency:
Completely achieved
Not fully achieved

4. Object Oriented Middleware System Comparisons
CORBA
COM/DCOM
JAVA/RMI
Access Transparency:
Completely achieved
Not fully achieved
Language Independency:
Achieved (IDL)
Achieved (MIDL)
Not achieved
Multiple Inheritance Class:
Yes No
Multiple Interface Class:

5. Object Oriented Middleware System Comparisons
CORBA
COM/DCOM
JAVA/RMI
At-most-once semantics:
Yes
Polymorphism:
Restricted (statically typed)
Attributes:
Treated as operations (implicit)
Treated as operations (explicit)

6. Object Oriented Middleware System Comparisons
CORBA
COM/DCOM
JAVA/RMI
Failures:
Standard exceptions and support type exception as part of IDL
Defines HResult (32-bit integer)
Standard exceptions and support type specific exception
Binary Encapsulation:
Yes
Binary Compatibility:

7. Object Oriented Middleware System Comparisons
CORBA
COM/DCOM
JAVA/RMI
Object References:
Supported
Not supported
Supported through rmic
Passing executable code:
Not allowed.
Not allowed
Allowed
Inheritance:
Yes. Root is Object
Yes. Root is IUnknown
Yes. Root is Remote.

8. Pros/Cons of Java/RMI Pros: Available since JDK 1.02
Hides the need to learn IDL from the user
Portable across many platforms
Can introduce new code to foreign JVMs

9. Pros/Cons of Java/RMI Cons: Works only with Java platform
Limitations on functionality
Security threats with remote code execution

10. So which is the best and which is the worst?
GOD KNOWS!!!