Running Rmi Server, Classnotfound

JAVA RMI ClassNotFound

from docs

The URL of a directory in which the classes are organized in
package-named sub-directories

so URL should point to classes root directory, more or less something like this:

-Djava.rmi.server.codebase=file://E:/Rmi/src

Try it out.

RMI UnmarshalException ClassNotFoundException server only

java.lang.ClassNotFoundException: nl.marktielemans.rmisorter.server.factory.ISortFactory
...
at sun.rmi.registry.RegistryImpl_Stub.rebind(Unknown Source)

The Registry doesn't have that class available in its CLASSPATH.

If you're using the java.rmi.server.codebase property you need to set it before exporting any remote objects, and the codebase needs to be something the Registry and the clients can use.

public static void addCodeBaseFor(Class<?> clazz) {
    System.setProperty("java.rmi.server.codebase", clazz.getProtectionDomain().getCodeSource().getLocation().toString());
}

This isn't going to work. The location on the server of the containing JAR file can't be seen from the client. Generally it is an http: or ftp: URL.

Java RMI and ClassNotFoundException

You are trying to send a serialized object of a class that is unknown to the server.

When you execute:

  Pi task = new Pi(Integer.parseInt(args[1]));
  BigDecimal pi = comp.executeTask(task);

The server doesn't really know what is Pi. And since the Pi class is a part of your API, it should be loaded on server, too.

When I have an application that needs to execute something remotely, using for example RMI, Spring Remoting or similar, I divide my project in 3 projects: API, Server and Client. The API project will have all interfaces and model classes relevant to the functionality (this project will result in a jar, and is more or less like your computer JAR). The server will import the API JAR, will implement the interfaces and make the service available through an Remote layer (like you did with your server), and the client as you did with your client.

When you work with serialization, the class itself must be known by both sides. What is then transferred is the state of the objects in order to rebuild it on the other side.

Serialization is the mechanism used by RMI to pass objects between
JVMs, either as arguments in a method invocation from a client to a
server or as return values from a method invocation.

A bit of Serialization on RMI By William Grosso (October 2001). And here a bit more info.

Running RMI Server, got errors with marshalling arguments and class not found

Summarizing the comment chain.

What is essential is that the registry should be aware of the Server stub. In order for this to happen, there are two options. Option one is the Registry and the Server to share the same VM. This can be achieved through

adding LocateRegistry.createRegistry()
In the beginning of the server main class.

Option two is

two configure the server to use automatic download of the stub files this can be achieved through java.rmi.server.codebase

example command

java -cp c:\home\ann\src;c:\home\ann\public_html\classes\compute.jar
     -Djava.rmi.server.codebase=file:/c:/home/ann/public_html/classes/compute.jar
     -Djava.rmi.server.hostname=mycomputer.example.com
     -Djava.security.policy=server.policy
        engine.ComputeEngine

this is taken from https://docs.oracle.com/javase/tutorial/rmi/running.html

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