Java: Run HTTP server on demand from my app?

Question

I want to write a simple P2P test app which uses HTTP as underlying protocol.
The app has to decide on demand, if it should act as a HTTP server, or as a HTTP client.

The classic way which I am aware of, would be to deploy the app on some existing HTTP server. But this is the wrong way for my intention. It has to be the other way: the server is started by the app (and only if it decides to).

Is there a way to execute the HTTP server part on demand (without deploying the app itself on a server)?

Can I do it by linking Glassfish or Tomcat libraries and call some "main" method?

Edit: IT WORKS!!!
I now tried Jetty along with JAX-RS (Jersey) successfully!
Thank you all.

(the REST class is trivial and left out)

package my.p2p;

import com.sun.jersey.spi.container.servlet.*;
import org.mortbay.jetty.*;
import org.mortbay.jetty.servlet.*;

public class Main {
  public static void main(String[] args)
      throws Exception {

    ServletHolder holder = new ServletHolder(ServletContainer.class);

    holder.setInitParameter("com.sun.jersey.config.property.resourceConfigClass",
      "com.sun.jersey.api.core.PackagesResourceConfig");
    holder.setInitParameter("com.sun.jersey.config.property.packages", "my.p2p.rest");

    Server server = new Server(8000);

    Context context = new Context(server, "/", Context.SESSIONS);
    context.addServlet(holder, "/*");
    server.start();
  }
}

Answer 1

You may use Jetty or some other embeddable HTTP server. From Jetty's web site:

Jetty is an open-source project providing a HTTP server, HTTP client and javax.servlet container. These 100% java components are full-featured, standards based, small foot print, embeddable, asynchronous and enterprise scalable. Jetty is dual licensed under the Apache License 2.0 and/or Eclipse Public License 1.0. Jetty is free for commercial use and distribution under the terms of either of those licenses.