A NoSuchObjectException is thrown if an attempt is made to invoke a method on an object that no longer exists in the remote virtual machine. If a NoSuchObjectException occurs attempting to invoke a method on a remote object, the call may be retransmitted and still preserve RMI's "at most once" call semantics. A NoSuchObjectException is also thrown by the method java.rmi.server.RemoteObject.toStub and by the unexportObject methods of java.rmi.server.UnicastRemoteObject.