Re: Java RMI questions and MyEclipse

=?ISO-8859-1?Q?Arne_Vajh=F8j?= <>
Tue, 02 Oct 2012 12:50:37 -0400
On 10/2/2012 12:16 PM, Clayton Cramer wrote:

I hope that I am asking this in the right group.

1. I am looking at the possibility of replacing our browser-based
JSP/Struts client talking to Java server classes with a thick client
written in Java. (Yes, for most enterprise systems, this would not
be a great idea, but for us it does make sense: we have a few hundred
PCs talking to our servers; there are never one time users connecting
to our servers unless it's a security breach.)

2. I I started with the Oracle demo where the client makes a request
for the value of pi to an arbitrary number of places, and the server
computes it and passes it back to the client.

I was able to get this working using javac and jar from the command
line (which involves bundling the class files into a JAR, copying it
over to the tomcat webapps directory). My guess is that there is some
way to set this up in MyEclipse so that it compiles and
redeploys--but it is not exactly obvious how to set this up.

I am using MyEclipse 9.1, Tomcat 5.0.28 (please don't laugh; we're
working on moving into modern times, and getting rid of our papyrus
and clay tablets).

I would recommend against using RMI here. A web container is not a
good RMI server.

Expose the functionality as web services and let your fat client
call those.

To simplify figuring out what is broken, I have taken the Oracle
tutorial code and put in a single project, divided into three
packages: client, compute, and engine. I can start the server
(engine) with the following DOS batch file:

java -cp "c:\Documents and Settings\ccramer\Workspaces\MyEclipse
-Djava.rmi.server.codebase=file:/c:\tomcat5\webapps\rmi\compute.jar engine.ComputeEngine

I can run the client side from the command line with the following
DOS batch file:

view plaincopy to clipboardprint? java -cp "c:\Documents and
-Djava.rmi.server.codebase=file:/c:\tomcat5\webapps\rmi\computer.jar client.ComputePi localhost %1%

where %1% is the parameter passed to the batch file specifying the
number of digits of pi to have the server side calculate and return.

Then I tried to get MyEclipse to start the server in pretty much the
equivalent way using the Run Configurations...:

Main.class: engine.ComputeEngine Classpath: default classpath and
c:\tomcat5\webapps\rmi\compute.jar Environment:

Code: ComputeEngine exception: java.rmi.ServerException:
RemoteException occurred in server thread; nested exception is:
java.rmi.UnmarshalException: error unmarshalling arguments; nested
exception is: java.lang.ClassNotFoundException: compute.Compute at

As you can see, there is a ClassNotFoundException: compute.Compute

I'm hard pressed to see why. If I do a jar -tf
c:\tomcat5\webapps\rmi\compute.jar I get:

Code: META-INF/ META-INF/MANIFEST.MF compute/Compute.class

Can you check the actual java command used when running inside


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