Why my RMI connection throw exceptions?

[long lingyu]

It throws exception:
java.rmi.ConnectException: Connection refused to host: localhost; nested exception is:
java.net.ConnectException: Connection refused: connect
at sun.rmi.transport.tcp.TCPEndpoint.newSocket(Unknown Source)
at sun.rmi.transport.tcp.TCPChannel.createConnection(Unknown Source)
at sun.rmi.transport.tcp.TCPChannel.newConnection(Unknown Source)
at sun.rmi.server.UnicastRef.newCall(Unknown Source)
at sun.rmi.registry.RegistryImpl_Stub.lookup(Unknown Source)
at java.rmi.Naming.lookup(Unknown Source)
at suncertify.db.DataFactory.getDatabase(DataFactory.java:83)
at suncertify.client.AloneFileChooser$1.actionPerformed(AloneFileChooser.java:70)
at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
at javax.swing.AbstractButton$ForwardActionEvents.actionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
at java.awt.Component.processMouseEvent(Unknown Source)
at java.awt.Component.processEvent(Unknown Source)
at java.awt.Container.processEvent(Unknown Source)
at java.awt.Component.dispatchEventImpl(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
at java.awt.Container.dispatchEventImpl(Unknown Source)
at java.awt.Window.dispatchEventImpl(Unknown Source)
at java.awt.Component.dispatchEvent(Unknown Source)
at java.awt.EventQueue.dispatchEvent(Unknown Source)
at java.awt.EventDispatchThread.pumpOneEventForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEventsForHierarchy(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.pumpEvents(Unknown Source)
at java.awt.EventDispatchThread.run(Unknown Source)
Caused by: java.net.ConnectException: Connection refused: connect
at java.net.PlainSocketImpl.socketConnect(Native Method)
at java.net.PlainSocketImpl.doConnect(Unknown Source)
at java.net.PlainSocketImpl.connectToAddress(Unknown Source)
at java.net.PlainSocketImpl.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.connect(Unknown Source)
at java.net.Socket.<init>(Unknown Source)
at java.net.Socket.<init>(Unknown Source)
at sun.rmi.transport.proxy.RMIDirectSocketFactory.createSocket(Unknown Source)
at sun.rmi.transport.proxy.RMIMasterSocketFactory.createSocket(Unknown Source)
... 31 more
When I write a test program from rmi ,it run correctly.

[George Marinkovich]

Hi Long,

        ...
at java.rmi.Naming.lookup(Unknown Source)
at suncertify.db.DataFactory.getDatabase(DataFactory.java:83)
        ...

It might be helpful to post your DataFactory.getDatabase method code.

[alzamabar]

Originally posted by long lingyu:
It throws exception:
at java.rmi.Naming.lookup(Unknown Source)
at suncertify.db.DataFactory.getDatabase(DataFactory.java:83)

Did you register the server with the Naming service?
Marco

[long lingyu]

My code:

public DataInterface getDatabase(Properties setting) {
String host = HOST;
String port = PORT;
host = setting.getProperty("HOST");
port = setting.getProperty("PORT");
lookupString = "rmi://" + host + ":" + port + "/" + RMI_SERVICE_NAME;
try {
return (DataInterface) Naming.lookup(lookupString);
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (RemoteException e) {
e.printStackTrace();
} catch (NotBoundException e) {
e.printStackTrace();
}
return null;
}

[Andrew: put the source code between [code] and [/code] UBB tags]
[ March 11, 2004: Message edited by: Andrew Monkhouse ]

[Andrew Monkhouse]

Hi Long,
I'll repeat Marco's question: Did you register the server with the Naming service?
(Actually, I would go even further back: have you started the registry? )
You may want to put a temporary line into your code which will allow you to see what your lookupString contains. So change your code to:

lookupString = "rmi://" + host + ":" + port + "/" + RMI_SERVICE_NAME;
System.out.println("lookup string = " + lookupString);

You might want to double check that your registry is listening on the port number you are using. You can normally do this by running "netstat -an" from a command prompt:

$ netstat -an
Active Internet connections (servers and established)
Proto Recv-Q Send-Q Local Address           Foreign Address         State
tcp        0      0 0.0.0.0:32768           0.0.0.0:*               LISTEN
tcp        0      0 127.0.0.1:32769         0.0.0.0:*               LISTEN
tcp        0      0 0.0.0.0:2401            0.0.0.0:*               LISTEN
tcp        0      0 0.0.0.0:515             0.0.0.0:*               LISTEN
tcp        0      0 127.0.0.1:8005          0.0.0.0:*               LISTEN
tcp        0      0 0.0.0.0:6566            0.0.0.0:*               LISTEN
tcp        0      0 0.0.0.0:8009            0.0.0.0:*               LISTEN
tcp        0      0 0.0.0.0:3306            0.0.0.0:*               LISTEN
[B]tcp        0      0 0.0.0.0:1099            0.0.0.0:*               LISTEN[/B]
tcp        0      0 0.0.0.0:139             0.0.0.0:*               LISTEN
tcp        0      0 0.0.0.0:108             0.0.0.0:*               LISTEN
tcp        0      0 0.0.0.0:110             0.0.0.0:*               LISTEN

See that line in bold? That tells me that I do have something running and listening on port 1099 (the standard RMI port).
This will look slightly different under MS Windows:

C:\>netstat -an
 
Active Connections
 
  Proto  Local Address          Foreign Address        State
[B]  TCP    0.0.0.0:1099           0.0.0.0:0              LISTENING[/B]
  TCP    192.168.1.55:1025      192.168.1.1:139        TIME_WAIT
  TCP    192.168.1.55:1026      0.0.0.0:0              LISTENING
  TCP    192.168.1.55:1026      192.168.1.1:139        ESTABLISHED
  TCP    192.168.1.55:137       0.0.0.0:0              LISTENING
  TCP    192.168.1.55:138       0.0.0.0:0              LISTENING
  TCP    192.168.1.55:139       0.0.0.0:0              LISTENING
  UDP    192.168.1.55:137       *:*
  UDP    192.168.1.55:138       *:*

But the important bit is that it is listening on port 1099, and that it is not bound to a specific address (I don't think you can bind Sun's RMI Registry to a specific address, but it doesnt hurt to check).
Also, regarding your catch blocks:

} catch (MalformedURLException e) {
e.printStackTrace();
} catch (RemoteException e) {
e.printStackTrace();
} catch (NotBoundException e) {
e.printStackTrace();
}

You might might want to do something a little more user friendly for your final submission.
Regards, Andrew

[long lingyu]

My server code:

    try {
        Registry myRegistry =
                LocateRegistry.createRegistry(Integer.parseInt(port));
        DataInterface dbServer = new DataRMIImpl(dbpath);
        String urlString =
                "rmi://localhost:" + port + "/" + RMI_SERVICE_NAME;
        myRegistry.rebind(RMI_SERVICE_NAME, dbServer);
    } catch (RemoteException e) {
        e.printStackTrace();
    }

What's the matter?
[Andrew: put the source code between [code] and [/code] UBB tags]
[ March 11, 2004: Message edited by: Andrew Monkhouse ]

[Andrew Monkhouse]

Hi Long,
I have edited your post to put the code between [code] and [/code] UBB tags. Doing this ensures that indenting is preserved, which makes the code easier to read.
When you are writing your post, there are a number of buttons just below the edit pane, which will insert the tags for you, so you don't have to remember what they are.
If you would like to edit your original post so that you can see what I have done, you can click on the button that is just above your post.
I cannot see what is wrong with this code.
Did you confirm that

Your server was running in another window while you were trying to run the client (and had not displayed any errors)?

You could see that your server was listening by using the netstat -an command?

The output when you printed the contents of the lookupString does contain all the right fields?

Regards, Andrew

[long lingyu]

1.How can I keep the server active? in command line: start rmiregistry or in program? I don't know the method to keep the server active in program.
2.Should there need a security file for the client connection?
I have test a simple RMI program. It work good. The steps are:
a. start rmiregistry <port>
b. rmic -v1.2
c. run server
d. run client with arguement -Djava.security.policy
It run.
In the project,I can't connect the server. When I use createRegistry(port),there are no port in the netstat -an display. Why?

[George Marinkovich]

Hi Long,

Originally posted by long lingyu:
1.How can I keep the server active? in command line: start rmiregistry or in program? I don't know the method to keep the server active in program.

Take a look at this thread: Topic: RMI Binding on localhost


2.Should there need a security file for the client connection?

No, it shouldn't be necessary.

I have test a simple RMI program. It work good. The steps are:
a. start rmiregistry <port>
b. rmic -v1.2
c. run server
d. run client with arguement -Djava.security.policy
It run.
In the project,I can't connect the server. When I use createRegistry(port),there are no port in the netstat -an display. Why?

Take a look at this thread: Topic: NX: Keep server running

[long lingyu]

I have solved this problem. I made a mistake. I start the server and then exit the JVM,the server is down. So the client can't connect to the server.

[long lingyu]

Another question,Should I package the policy file? or RMI don't need this file?

[Andrew Monkhouse]

Hi Long,
Glad to see your programs are now working.
you should not need a policy file for this assignment, and the newer assignments (Hotel and Contractors) forbid "the installation of a security manager". So I recommend you do not use a policy file.
(Note that although you should not need a policy file for this assignment, you may need one in real life if you ever need to use RMI).
Regards, Andrew