111.  Introduction to Java RMI

Rev. 1.0

 

This one-day module offers a straightforward introduction to Java’s Remote Method Invocation (RMI) framework. It is designed to teach experienced Java programmers how to get up and running with RMI for practical applications. The RMI architecture is discussed, and students work through a simple RMI server implementation process: interface, implementation, and server. Then more of the mechanics of RMI in practical use are studied, starting with a look at some of the generated code for stubs and skeletons. This gives a better understanding of the RMI marshaling process. Students then work on a more complex system and confront design issues such as when and where to use remote object references versus serialized state or value objects.

 

LEARNING OBJECTIVES

 

·         Understand the role of Java RMI in distributed Java software development.

·         Understand the relationship between RMI and various J2EE technologies such as JNDI, EJB, and CORBA.

·         Understand the RMI framework and architecture, especially the role of generated stubs and skeletons.

·         Implement simple RMI clients and servers.

·         Know what files must be deployed to a client host for the RMI client to function correctly, and likewise for an RMI server.

·         Understand the RMI marshaling process, especially what sorts of method arguments and return values travel over the wire and which remain to be referenced remotely.

·         Make well-motivated choices between remote objects and serialized objects in RMI design and implementation.

 

Course Duration:  1 day.

 

Prerequisites:  Experience in Java Programming is essential. The student must be comfortable with object-oriented Java, interfaces and abstract classes. Knowledge of the Serialization API is important as well.

 

1.      RMI Architecture

Motivation for RMI

RMI and EJB

RMI and CORBA

Overview of RMI Architecture

Stubs and Skeletons

Remote Reference Layer

RMI Transport

Lifetime of a Remote Method Invocation

RMI Registry

Naming and URL Resolution

RMI Up and Running

 

2.      RMI Implementation

Interface Design

The Remote Interface

Implementation Classes

The RemoteObject and RemoteServer Classes

The UnicastRemoteObject Class

Server Implementation

Using the Registry

Client Implementation

Code Deployment

 

3.      Practical RMI

Stub Source Code

RMI Marshaling

Skeleton Source Code

Diagnostic Code Using RemoteServer

Passing Objects

The Factory Pattern

Serialization vs. Remote Reference

Designing for Latency

The Value Object Pattern

Exception Handling

 

Appendix A. References

 

System Requirements

 

Hardware (Recommended):

 

·         CPU:          Pentium 200 or equivalent or faster

·         RAM:          64 MB (64 MB)

·         Disk:           200 MB (500 MB)

 

Software:

 

JDK version 1.2 or higher – 1.3 is recommended, preferably with the Core API source code unpacked into directories and preferably with full HTML documentation also installed. No commercial builder tools / IDEs are required, but they can be used if preferred.