How Objects Communicate

Not all objects are written in the same language and running on the same machine. So in distributed environment and in order to have interface among all different objects, the only solution is to separate the interface (how the objects communicate with each other) from the implementation (how the object performs its job). This is done using Interface Definition Language (IDL). 

Here there is a difference between DCOM and CORBA, Microsoft uses MIDL, while CORBA uses CORBA IDL. Objects talk to each other across the network, using ORB (for CORBA) and Microsoft uses different DCOM products. Multiple CORBA ORBs communicate via a standard communications protocol known as Internet Inter-ORB Protocol (HOP) as shown in figure A2-4, while Microsoft uses DCOM protocol as shown in figure A2-5. EJB uses its own standard communication for Java-to-Java communication called Remote Method Invocation (RMI). The term BOA is used for Basic Object Adapter and RPC is used for Remote Procedure Call . 

Client Stub (Proxy) Logical Layer (Implementation Repository) Server Stub (Skeleton) 

---

Design of Practical Enterprise Safety Management System 177 How Objects Communicate ... 

---