CODEWITHSUNDEEP
javarmi
kebs
kebs

Reputation: 6707

Why does the server program not exit?

I have a fundamental question about Java RMI, I have mostly a C++ background, and there is something I don't get with RMI.

To be clear, I am able to make it work fine, but it's something about the program lifetime.

If I have a toy Java program such as:

public class Test1 {
    public static void main(String args[]) {
        System.out.println( "start !" );
    }
}

when I run it from shell, it prints the message and exits.

If I want to use sockets, then I need to have some infinite loop in my server, that will wait for incoming connections, process them, then start over.

ServerSocket socketserver = new ServerSocket( port_id );
System.out.println( "server: waiting"  );   

while(true) {
    Socket socket = socketserver.accept(); 
    System.out.println( "server: incoming connection" );
    ... do stuff...
    socket.close();
}

Now, say I have an RMI server with the following main() method:

public static void main(String args[]) throws Exception {
    System.out.println( "RMI server started !" );
    MyObject obj = new MyObject();

    Naming.bind( "//localhost/myObject", obj );
    System.out.println( "Done!" );
}

Assuming the class MyObject can be found, and that everything compiles fine.

If I run this from the shell, then although it does print the last message and that is no infinite loop after that line, the program does not exit.

Questions:

The linked question answers the first question, but not the second. Neither does the Oracle tutorial (unless I missed that ?)

Upvotes: 0

Views: 321

Answers (2)

user207421
user207421

Reputation: 310985

  1. RMI creates a background non-daemon thread for every port it is listening to. That thread will only exit when all the objects that are exported on its port have been unexported, either explicitly or via DGC.
  2. Unexport the remote objects, including the Registry if you started it yourself in the JVM.

Upvotes: 1

SPlatten
SPlatten

Reputation: 5760

You should implement a thread that listens for client connections and creates worker threads to respond to clients. When the main thread terminated the joined threads will also terminate.

Upvotes: 0

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