Updated: 05/03/2012
To successfully set up RMI communications, you need three components: rmiregistry, a server, and a client. Once rmiregistry and the server are running, the client should be able to connect to the server successfully. See generic RMI server-client implementations on how to connect a client to a server. This tutorial helps you set up such necessary components in Eclipse.
First, run rmiregistry as an external program in Eclipse. To do this, go to Run → External Tools → External Tools Configurations... from the menu. Create a new Program configuration, which will look like the figure below. Browse File System... to locate your rmiregistry, which is usually in the bin directory of the Java distribution. Save and run this external tool. rmiregistry can keep running in the background, but be sure to terminate it before you close Eclipse.
Caveat: If you have Java 6 Update 29, you will need to update it to a more recent version (e.g., Update 32) because its rmiregistry disallows reading class files in the codebase (see below) for an erroneous security reason.
Next, go to the main method which spawns the server. You will need to provide a correct codebase for the server to run properly. To do this, go to Run → Run Configurations... from the menu. Create a new Java Application configuration, which will look like the figure below. (If you have run this main method before, go to its configuration instead.) You will need to provide an argument to the Java virtual machine as in the figure, where ${workspace_loc:hw7/bin/} refers to the directory containing .class files of your server implementation. For instance, if your server implementation ServerImpl is in package myname, the desired directory should contain a subdirectory myname containing ServerImpl.class. The Eclipse's workspace_loc variable refers to the workspace directory.
Caveat: If your path contains a space, this might not work. Consider renaming your directory to eliminate spaces.
With rmiregistry running, you should now be able to run the server. In contrast with rmiregistry, you should kill your server even if it fails to run, because the main method will not exit.
Now you should be able to run your client applet successfully.
Updated: 05/03/2012