Is it possible to use RMI bidirectional between two classes?

Question

I want to share some information between two classes (A and B), which are running in different java programs. Instead of writing a whole communication protocol I want to use

Answer 1

If you pass B as an argument to a method in A and then use that reference to call a method on B I am fairly certain that a reverse connection is established, and I am fairly certain that RMI Registry is created for the JVM where B resides. At some point this got us into a bit of trouble with particularly strict firewall rules. Our code looked a little something like

Web Server

public int uploadFile(FileItem fileItem){
    return ApplicationClassLoader
        .get(DocumentManager.class)
        .attachFile(new RemoteInputStreamImpl(fileItem.getInputStream());
    )
}

Application Server

public int attachFile(RemoteInputStream in){
    ...

    byte[] buffer;
    while((buffer = in.read(1024)) != null) // Would return null to indicate EOF
      // Do some stuff

    return documentId;       
}