Someone

/** 
 * The HelloWorldApp class implements an application that
 * simply prints "Hello World!" to standard output.
 */

/*

class HelloWorldApp {
    public static void main(String[] args) {
        System.out.println("Hello World!"); // Display the string.
    }
}

*/

import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpSession;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.OutputStream;
import java.io.PrintWriter;


public class HelloWorldServlet extends HttpServlet {
  // Redirect to handle()                                                       
  public void doGet(HttpServletRequest httpRequest,
                    HttpServletResponse httpResponse) {
    handle(httpRequest, httpResponse);
  }

  // Redirect to handle()                                                       
  public void doPost(HttpServletRequest httpRequest,
                     HttpServletResponse httpResponse) {
    handle(httpRequest, httpResponse);
  }

    private void handle(HttpServletRequest httpRequest,
                      HttpServletResponse httpResponse) {
    OutputStream os = null;
    try {
      os = httpResponse.getOutputStream();
      PrintWriter pw = new PrintWriter(os);
      pw.println("Hello, World!");
      pw.flush();
      pw.close();
    } catch (IOException ioex) {
      ioex.printStackTrace();
    } finally {
      if (os != null) os.close();
    }
  }
}