THE UNIVERSITY OF WESTERN AUSTRALIA

School of Computer Science & Software Engineering

CITS3213 CONCURRENT SYSTEMS

Mini Laboratory Sheet on Java Remote Method Invocation (RMI)

Please note that javac is supposed to generate the stub class in Java 1.6. However, I had to run rmic (as described below) even though I have java 1.6 in my machine. You should follow the instructions below and report if you have any problem.

Tasks

• Hello.java contains the interface.
• HelloImplementation.java contains the server code.
• RemoteHelloClient.java contains the client code.
  Note : You will find the following line in this code :
  private static final String registry = "//bilby.cs.uwa.edu.au/";
  You have to change 'bilby' to the name of your machine.
• test.policy is the file with security policy. This will be needed later.
• We will first run both the client and the server on the same machine under the same login i.e., your login.
• Compile the two files HelloImplementation.java and RemoteHelloClient.java in the usual way, i.e., by using javac
• Use the RMI compiler rmic to compile the HelloImplementation class file :

  rmic HelloImplementation

  This will create the stub file : HelloImplementation_Stub.class

• Now start the RMI registry in the background :

  rmiregistry&

• Now bind the server to the RMI registry :

  java -Djava.security.policy=test.policy HelloImplementation

• Now execute the client :

  java -Djava.security.policy=test.policy RemoteHelloClient

• You will get the output from the server.
• Remember to set read permission for all your files including test.policy

• Let your current machine be the host and a friend's machine (where your friend is logged in) be the client.
• ftp the files HelloImplementation_Stub.class and test.policy in a directory in your friend's machine.
• ftp also the file RemoteHelloClient.java in the same directory. Compile this file through javac and run it :

  java -Djava.security.policy=test.policy RemoteHelloClient

• Try with different messages in HelloImplementation.java. Remember, every time you change this file in the server, you have to compile it and you have to run rmic to generate the stub and skeleton.

Additional Larger Tasks

You can also run the larger example that I covered in the second RMI lecture. Here is the link to the relevant section of Java tutorial. You can cut and paste the code from the above link.

Modify the Java code for the producer-consumer example (presented in lectures) so that the Producer and Consumer objects are clients running on different computers that use RMI to invoke methods on a remote Buffer object.

• Here's the code to modify: Producer.java, Consumer.java, and Buffer.java.
• You will need to create an appropriate interface, and follow roughly the steps in the first example (above).
• You'll also need to write main methods for both clients (Producer and Consumer) and the server (Buffer). Again, follow the above example.

May, 2008.