Re: I got some problems when using use activation mechanism of RMI

You're right.
But I find that running rmid should be as follow:
rmid -J-Dsun.rmi.activation.execPolicy=none
-J-Djava.security.policy=rmid.policy
And the program cannot run correctly when using
Activatable.exportObject(this , id , 0);
If the ProductImpl is:
public class ProductImpl extends UnicastRemoteObject implements Product
{
private String name;
private static final long serialVersionUID = 6613571299445532659L;
public ProductImpl(ActivationID id , MarshalledObject object)throws
IOException, ClassNotFoundException{
//super(id , 0);
Activatable.exportObject(this , id , 0);
name=(String)object.get();
System.out.println("marshalledobject");
}

public String getDescription() throws RemoteException {
return "I am a " + name + ". Buy me!";
}
}
I still get the exception when the client runs.
java.rmi.activation.ActivateFailedException: failed to activate object;
nested exception is:
java.rmi.activation.ActivationException: exception in object
constructor; nested exception is:
java.rmi.server.ExportException: object already exported
at sun.rmi.server.ActivatableRef.activate(Unknown Source)
at sun.rmi.server.ActivatableRef.invoke(Unknown Source)
at ProductImpl_Stub.getDescription(Unknown Source)
at ProductClient.main(ProductClient.java:20)
Caused by: java.rmi.activation.ActivationException: exception in object
constructor; nested exception is:
java.rmi.server.ExportException: object already exported
at
sun.rmi.server.ActivationGroupImpl.newInstance(ActivationGroupImpl.java:286)
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:324)
at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:261)
at sun.rmi.transport.Transport$1.run(Transport.java:148)
at java.security.AccessController.doPrivileged(Native Method)
at sun.rmi.transport.Transport.serviceCall(Transport.java:144)
at
sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:460)
at
sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:701)
at java.lang.Thread.run(Thread.java:534)
at
sun.rmi.transport.StreamRemoteCall.exceptionReceivedFromServer(StreamRemoteCall.java:247)
at
sun.rmi.transport.StreamRemoteCall.executeCall(StreamRemoteCall.java:223)
at sun.rmi.server.UnicastRef.invoke(UnicastRef.java:133)
at java.rmi.activation.ActivationGroup_Stub.newInstance(Unknown
Source)
at
sun.rmi.server.Activation$ObjectEntry.activate(Activation.java:1481)
at sun.rmi.server.Activation$GroupEntry.activate(Activation.java:1132)
at
sun.rmi.server.Activation$ActivatorImpl.activate(Activation.java:262)
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:324)
at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:261)
at sun.rmi.transport.Transport$1.run(Transport.java:148)
at java.security.AccessController.doPrivileged(Native Method)
at sun.rmi.transport.Transport.serviceCall(Transport.java:144)
at
sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:460)
at
sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:701)
at java.lang.Thread.run(Thread.java:534)
at
sun.rmi.transport.StreamRemoteCall.exceptionReceivedFromServer(Unknown
Source)
at sun.rmi.transport.StreamRemoteCall.executeCall(Unknown Source)
at sun.rmi.server.UnicastRef.invoke(Unknown Source)
at sun.rmi.server.Activation$ActivatorImpl_Stub.activate(Unknown
Source)
at java.rmi.activation.ActivationID.activate(Unknown Source)
... 4 more
Caused by: java.rmi.server.ExportException: object already exported
at sun.rmi.transport.ObjectTable.putTarget(ObjectTable.java:171)
at sun.rmi.transport.Transport.exportObject(Transport.java:69)
at
sun.rmi.transport.tcp.TCPTransport.exportObject(TCPTransport.java:190)
at
sun.rmi.transport.tcp.TCPEndpoint.exportObject(TCPEndpoint.java:382)
at sun.rmi.transport.LiveRef.exportObject(LiveRef.java:116)
at
sun.rmi.server.UnicastServerRef.exportObject(UnicastServerRef.java:145)
at
sun.rmi.server.UnicastServerRef.exportObject(UnicastServerRef.java:129)
at java.rmi.activation.Activatable.exportObject(Activatable.java:507)
at java.rmi.activation.Activatable.exportObject(Activatable.java:399)
at ProductImpl.<init>(ProductImpl.java:22)
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native
Method)
at
sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39)
at
sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27)
at java.lang.reflect.Constructor.newInstance(Constructor.java:274)
at
sun.rmi.server.ActivationGroupImpl$1.run(ActivationGroupImpl.java:241)
at java.security.AccessController.doPrivileged(Native Method)
at
sun.rmi.server.ActivationGroupImpl.newInstance(ActivationGroupImpl.java:222)
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:324)
at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:261)
at sun.rmi.transport.Transport$1.run(Transport.java:148)
at java.security.AccessController.doPrivileged(Native Method)
at sun.rmi.transport.Transport.serviceCall(Transport.java:144)
at
sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:460)
at
sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:701)
at java.lang.Thread.run(Thread.java:534)

It seems that the server has exported the object, and the client cannot
export it again.

EJP wrote:
Zheng Da wrote:

public class ProductImpl extends UnicastRemoteObject implements Product

You must either change this to 'extends Activatable implements Product',
in which case you should replace the following quoted line by super(id,
0); or else restore the following quoted line as it is:

//Activatable.exportObject(this , id , 0);

There may be other problems.

.