---
title: "CORBA services; object adapter functions"
subject: "Distributed System"
chapter: 4
key: "semester_7/distributed_system:corba-services-object-adapter"
source: https://www.bctengineer.com/q/semester_7/distributed_system/corba-services-object-adapter
site: BCT Engineering
---

# CORBA services; object adapter functions

Distributed System · Chapter 4: Distributed Heterogeneous Applications and CORBA

- Asked in: 2071 Shrawan, 4 marks
- Video: [CORBA : What is CORBA in Distributed System ? : Distributed System](https://www.youtube.com/watch?v=PpbJq5OA66Y) — Computer Science Academy By Dinesh Sir
- Answer checked by Claude Opus 5.5 (high effort) on 2026-10-14
- Page: https://www.bctengineer.com/q/semester_7/distributed_system/corba-services-object-adapter
- Whole chapter: https://www.bctengineer.com/md/semester_7/distributed_system/chapter-4

## Question

Write a short note on services provided by CORBA with the functions of Object Adapter.

## Short answer

CORBA services include naming, trading, events, transactions, concurrency, security, and lifecycle. The Object Adapter (POA) generates object references, registers implementations, activates/deactivates objects, demultiplexes requests to servants, manages threading, and provides security hooks, acting as the glue between the ORB and object implementations.

## Answer

#### Services provided by CORBA
CORBA gives, through the ORB, location-transparent and language-independent invocation of remote objects. Its standard object services are:
- **Naming** (name to object reference) and **Trading** (find by property).
- **Event/Notification** for asynchronous messaging.
- **Life cycle** (create, copy, move, delete) and **Persistence** of objects.
- **Transaction** and **Concurrency control** for consistent access.
- **Security** (authentication, access control, encryption).
- **Query, Relationship, Time, Licensing, Collection** services.

#### Functions of the Object Adapter
The Object Adapter (BOA, later POA - Portable Object Adapter) sits between the ORB core and the object implementation (servant). Its functions:
1. **Generates and interprets object references** (object keys) of objects it manages.
2. **Registers** object implementations with the ORB (and the implementation repository).
3. **Activates and deactivates** servers and objects on demand (activation policies such as persistent or transient).
4. **Demultiplexes and dispatches** an incoming request to the correct servant and method via the skeleton.
5. **Manages threading policy** for concurrent requests.
6. Provides **security and lifetime management** hooks and hides the servant details from the ORB.

```text
 ORB core --> Object Adapter --> Skeleton --> Servant
```

## Check yourself

The answer's key points as multiple-choice questions, with the correct option and why.

1. Where does the Object Adapter sit?
   A. Between client and stub
   B. Between the ORB core and the servant
   C. Inside the client
   D. Between networks
   Answer: B. It hides the ORB from the implementation. (Key point: Object adapter position)

2. Which is a function of the object adapter?
   A. Define IDL
   B. Compile stubs
   C. Demultiplex and dispatch requests to the correct servant via the skeleton
   D. Encrypt data
   Answer: C. It also generates object references and activates objects. (Key point: Dispatch)

3. What is POA?
   A. Portable Object Adapter, the later standard replacing BOA
   B. A naming service
   C. A protocol
   D. A stub
   Answer: A. BOA was the older Basic Object Adapter. (Key point: BOA vs POA)

4. Which service finds objects by property?
   A. Naming
   B. Trading
   C. Life cycle
   D. Concurrency control
   Answer: B. Naming maps name to reference; Trading searches by property. (Key point: Services)

## Related in Distributed System

- [Object adapter and CORBA invocation](https://www.bctengineer.com/question.md?key=semester_7%2Fdistributed_system%3Aobject-adapter-invocation) — Distributed System, chapter 4
- [CORBA invocation methods and services](https://www.bctengineer.com/question.md?key=semester_7%2Fdistributed_system%3Acorba-invocation-services) — Distributed System, chapter 4, asked 3×
- [JINI goals, CORBA services, OS support](https://www.bctengineer.com/question.md?key=semester_7%2Fdistributed_system%3Aos-support-jini-corba) — Distributed System, chapter 3
- [Short note: CORBA services](https://www.bctengineer.com/question.md?key=semester_7%2Fdistributed_system%3Acorba-services-note) — Distributed System, chapter 4
- [IDL and CORBA RMI with services](https://www.bctengineer.com/question.md?key=semester_7%2Fdistributed_system%3Aidl-corba-rmi) — Distributed System, chapter 4
- [Middleware role; CORBA and services](https://www.bctengineer.com/question.md?key=semester_7%2Fdistributed_system%3Amiddleware-corba-services) — Distributed System, chapter 4