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classloaderrmi

java.rmi.UnmarshalException: error unmarshalling return; nested exception is:java.lang.ClassNotFoundException:

I have the following situation:

Using RMI, i noticed that under a specific situation, the RMI client did not have the class whose instance was sent via RMI. So, I sent the class in the shape of Byte [] and then loaded it with a class loader i defined.

The code in the client side is something like:

pp = plugins.getPanelClasses(); //RMI method
panelClassLoader pcl = new panelClassLoader(); //simple class loader defined by me
String name = pcl.defineClass(pp);

Then, i ask in the client side by the instance of the class loaded:

HashMap<String, PluginPanel> panels = null;
try
{
panels = plugins.getSettingsPanels();
} catch (RemoteException ex)
{
    Logger.getLogger(ServerOptions.class.getName()).log(Level.SEVERE, null, ex);
}

PluginPanel is an interface whose implementing classes are not always in the client...

and the class loader is:

private class panelClassLoader extends ClassLoader
{

    public panelClassLoader(ClassLoader parent)
    {
        super(parent);
    }

    public panelClassLoader()
    {
        super(getSystemClassLoader());
    }

    public String defineClass(byte[] b)
    {
        Class c = super.defineClass(null, b, 0, b.length);

        resolveClass(c);

        return c.getName();
    }
}

Nevertheless, I'm stuck with the following error: java.rmi.UnmarshalException: error unmarshalling return; nested exception is: java.lang.ClassNotFoundException: pt.ua.dicoogle.IndexPlugin.CPanel (no security manager: RMI class loader disabled) at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:178) at java.rmi.server.RemoteObjectInvocationHandler.invokeRemoteMethod(RemoteObjectInvocationHandler.java:178) at java.rmi.server.RemoteObjectInvocationHandler.invoke(RemoteObjectInvocationHandler.java:132) at $Proxy22.getSettingsPanels(Unknown Source) at pt.ua.dicoogle.rGUI.client.windows.ServerOptions.(ServerOptions.java:176)

Caused by: java.lang.ClassNotFoundException: pt.ua.dicoogle.IndexPlugin.CPanel (no security manager: RMI class loader disabled) at sun.rmi.server.LoaderHandler.loadClass(LoaderHandler.java:375) at sun.rmi.server.LoaderHandler.loadClass(LoaderHandler.java:165) at java.rmi.server.RMIClassLoader$2.loadClass(RMIClassLoader.java:620) at java.rmi.server.RMIClassLoader.loadClass(RMIClassLoader.java:247) at sun.rmi.server.MarshalInputStream.resolveClass(MarshalInputStream.java:197) at java.io.ObjectInputStream.readNonProxyDesc(ObjectInputStream.java:1574) at java.io.ObjectInputStream.readClassDesc(ObjectInputStream.java:1495) at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1731) at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1328) at java.io.ObjectInputStream.readObject(ObjectInputStream.java:350) at java.util.HashMap.readObject(HashMap.java:1030) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25) at java.lang.reflect.Method.invoke(Method.java:597) at java.io.ObjectStreamClass.invokeReadObject(ObjectStreamClass.java:974) at java.io.ObjectInputStream.readSerialData(ObjectInputStream.java:1848) at java.io.ObjectInputStream.readOrdinaryObject(ObjectInputStream.java:1752) at java.io.ObjectInputStream.readObject0(ObjectInputStream.java:1328) at java.io.ObjectInputStream.readObject(ObjectInputStream.java:350) at sun.rmi.server.UnicastRef.unmarshalValue(UnicastRef.java:306) at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:155)

Any sugestion?

Solution

  • You would have to call the remote method in the context of that class loader. Not a good scheme. Have a good look at the RMI codebase feature, it is designed for exactly this situation.