FULL PRODUCT VERSION :
java version "9-ea"
Java(TM) SE Runtime Environment (build 9-ea+111)
Java HotSpot(TM) Client VM (build 9-ea+111, mixed mode)

ADDITIONAL OS VERSION INFORMATION :
Microsoft Windows [Version 6.1.7601]

A DESCRIPTION OF THE PROBLEM :
Running an RMI application over webstart now breaks, due to incorrect modularisation.

REGRESSION. Last worked in version 8u77

ADDITIONAL REGRESSION INFORMATION:
java version "9-ea"
Java(TM) SE Runtime Environment (build 9-ea+111)
Java HotSpot(TM) Client VM (build 9-ea+111, mixed mode)

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
1. Set up and export an RMI service at a well-known address (see example code Server.java)
1a) javac Server.java
1b) java -cp . Server
2. Write a small client to connect to it and deploy over webstart with full permissions (see example code Test.java)
2a) javac Test.java
2b) jar mcf allperms-mf test.jar Test.class
2c) jarsigner test.jar signer-alias
3. Launch the provided webstart file

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
The client should connect with no error (assuming no firewall, etc., etc)
ACTUAL -
The client fails to start

ERROR MESSAGES/STACK TRACES THAT OCCUR :
java.lang.IllegalAccessError: class java.rmi.server.RMIClassLoader (in module java.rmi) cannot access class com.sun.jnlp.JNLPRMIClassLoaderSpi (in module jdk.javaws) because module jdk.javaws does not export com.sun.jnlp to module java.rmi
at java.rmi.server.RMIClassLoader.initializeProvider(java.rmi@9-ea/RMIClassLoader.java:689)
at java.rmi.server.RMIClassLoader.access$000(java.rmi@9-ea/RMIClassLoader.java:110)
at java.rmi.server.RMIClassLoader$1.run(java.rmi@9-ea/RMIClassLoader.java:120)
at java.rmi.server.RMIClassLoader$1.run(java.rmi@9-ea/RMIClassLoader.java:119)
at java.security.AccessController.doPrivileged(java.base@9-ea/Native Method)
at java.rmi.server.RMIClassLoader.<clinit>(java.rmi@9-ea/RMIClassLoader.java:118)
at sun.rmi.server.MarshalInputStream.resolveProxyClass(java.rmi@9-ea/MarshalInputStream.java:256)
at java.io.ObjectInputStream.readProxyDesc(java.base@9-ea/ObjectInputStream.java:1564)
at java.io.ObjectInputStream.readClassDesc(java.base@9-ea/ObjectInputStream.java:1520)
at java.io.ObjectInputStream.readOrdinaryObject(java.base@9-ea/ObjectInputStream.java:1779)
at java.io.ObjectInputStream.readObject0(java.base@9-ea/ObjectInputStream.java:1356)
at java.io.ObjectInputStream.readObject(java.base@9-ea/ObjectInputStream.java:368)
at sun.rmi.registry.RegistryImpl_Stub.lookup(java.rmi@9-ea/Unknown Source)
at java.rmi.Naming.lookup(java.rmi@9-ea/Naming.java:101)
at Test.main(Test.java:5)
at sun.reflect.NativeMethodAccessorImpl.invoke0(java.base@9-ea/Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(java.base@9-ea/NativeMethodAccessorImpl.java:62)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(java.base@9-ea/DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(java.base@9-ea/Method.java:531)
at com.sun.javaws.Launcher.executeApplication(jdk.javaws@9-ea/Launcher.java:1780)
at com.sun.javaws.Launcher.executeMainClass(jdk.javaws@9-ea/Launcher.java:1715)
at com.sun.javaws.Launcher.doLaunchApp(jdk.javaws@9-ea/Launcher.java:1563)
at com.sun.javaws.Launcher.run(jdk.javaws@9-ea/Launcher.java:164)
at java.lang.Thread.run(java.base@9-ea/Thread.java:804)


REPRODUCIBILITY :
This bug can be reproduced always.

---------- BEGIN SOURCE ----------
// Server.java
import java.rmi.registry.*;
import java.rmi.server.*;

public class Server {
        public static void main(String[] args) throws Exception {
                Registry r = LocateRegistry.createRegistry(1099);
                r.bind ("Toto", new UnicastRemoteObject () {});
        }
}

// Test.java
import java.rmi.Naming;

public class Test {
        public static void main(String[] args) throws Exception {
                Naming.lookup("rmi://testmachine:1099/Toto");
        }
}

// test.jnlp
?xml version="1.0" encoding="utf-8"?>
<jnlp spec="6.0+" codebase="http://www.example.com/webstart" href="test.jnlp">
  <security>
      <all-permissions/>
  </security>
  <resources>
    <j2se version="1.8+" href="http://java.sun.com/products/autodl/j2se" initial-heap-size="64m" max-heap-size="384m" java-vm-args="-ea"/>
    <jar href="test.jar" main="true"/>
  </resources>
  <application-desc main-class="Test"/>
</jnlp>

---------- END SOURCE ----------