Two processes are listening on the same port, how is that possible?

Question

Java

Windows 8.1 Pro
Launched and running tomcat (7.0.72.0 JVM 1.7.0_13-b20) on port 8080
Launched HelloWorld example on jetty

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.ServletException;
import java.io.IOException;
import org.eclipse.jetty.server.Server;
import org.eclipse.jetty.server.Request;
import org.eclipse.jetty.server.handler.AbstractHandler;

public class WebServer extends AbstractHandler {
  
  public void handle(String target, Request baseRequest, HttpServletRequest request, HttpServletResponse response)
      throws IOException, ServletException {
    response.setContentType("text/html;charset=utf-8");
    response.setStatus(HttpServletResponse.SC_OK);
    baseRequest.setHandled(true);
    response.getWriter().println("<h1>Hello World</h1>");
  }

  public static void main(String[] args) throws Exception {
    Server server = new Server(8080);
    server.setHandler(new WebServer());

    server.start();
    server.join();
  }
}

I expected to see an Exception (because port 8080 is already taken), but the application started normally:

2017-02-01 12:21:02.029:INFO::main: Logging initialized @
132ms
01 12:21:02.116:INFO:oejs.ServerConnector:main: Started [email protected]{HTTP/1.1}{0.0.0.0:8080}
2017-02-01 12:21:02.117:INFO:oejs.Server:main: Started @222ms

D:\>netstat -ano|find /i "8080"
TCP 0.0.0.0:8080 0.0.0.0:0 LISTENING 5536
TCP 0.0.0.0:8080 0.0.0.0:0 LISTENING 2464
TCP [::]:8080 [:: ]:0 LISTENING 5536

D:\>tasklist|find /i "tom"
tomcat7.exe 2464 Services 0 185916 KB
D:\>tasklist|find /i "java"
javaw.exe 5536 Console 1 26864 KB