Question

When I test an RMI client and server with the class files it works without any issue on two different machines. Now when I do the same thing with a jar the client fails to connect to the RMIRegistry on the server. Then when I test with the jar on the same machine, the client can connect to the server (even over the network ip and not localhost).

I suspect this has something to do with the RMI registry, but i’m a total novice at RMI, so I have no clue…

I create an RMIRegistry like so:

rmiregistry = LocateRegistry.createRegistry(ServiceConstraints.REGISTRY_PORT);
rmiService = (RmiSubjectService) UnicastRemoteObject.exportObject(this,
                    ServiceConstraints.REGISTRY_PORT);
rmiregistry.rebind("RmiService", rmiService);

The client connects like this:

remoteService = (RmiSubjectService) Naming.lookup("/" + host + ":"+ port + "/RmiService");

The error I get on the client when running with a jar:

java.rmi.ConnectException: Connection refused to host: 192.168.2.132; nested exception is:
        java.net.ConnectException: Connection timed out: 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 ch.uzh.ifi.group10.client.Client.subscribe(Client.java:148)
        at ch.uzh.ifi.group10.client.Client.main(Client.java:242)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
        at java.lang.reflect.Method.invoke(Unknown Source)
        at org.eclipse.jdt.internal.jarinjarloader.JarRsrcLoader.main(JarRsrcLoa
der.java:58)
Caused by: java.net.ConnectException: Connection timed out: 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.SocksSocketImpl.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 S
ource)
        at sun.rmi.transport.proxy.RMIMasterSocketFactory.createSocket(Unknown S
ource)
        ... 13 more

Answer 1

The problem did turn out to be the network. Specifically it was that I didn’t realize that my firewall was blocking the socket, so I could not connect.