A Built-In Java HttpServer

The com.sun.net.httpserver package was introduced with JDK 1.6 and enables the implementation of embedded HTTP servers:

import com.sun.net.httpserver.HttpContext;
import com.sun.net.httpserver.HttpServer;
import java.io.IOException;
import java.io.OutputStream;
import java.net.InetSocketAddress;

//...

String payload = "duke";
HttpServer server = HttpServer.create(new InetSocketAddress(4250), 0);
HttpContext context = server.createContext("/java");
context.setHandler((he) -> {
	he.sendResponseHeaders(200, payload.getBytes().length);
	final OutputStream output = he.getResponseBody();
	output.write(payload.getBytes());
	output.flush();
	he.close();
});
server.start();

Test: curl -i http://localhost:4250/java returns:

HTTP/1.1 200 OK
Date: Thu, 09 Jul 2015 02:48:37 GMT
Content-length: 4

duke%    

Warning: The packages com.sun.* are not part of the supported, public interface and may even disappear in upcoming Java releases.