Java Servlet Programing Laungage

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.0"
 xmlns="http://java.sun.com/xml/ns/javaee"
 xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
 http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">
 <servlet>
  <servlet-name>randomValueServlet</servlet-name>
  <servlet-class>r4r.servlet.randomValueServlet</servlet-class>
 </servlet>
 <servlet-mapping>
  <servlet-name>randomValueServlet</servlet-name>
  <url-pattern>/randomValueServlet</url-pattern>
 </servlet-mapping>
 <session-config>
  <session-timeout>
   30
  </session-timeout>
 </session-config>
</web-app>

Index.jsp

<%-- 
Document   : index.jsp
--%>
<%@page contentType="text/html" pageEncoding="UTF-8"%>
<!DOCTYPE html>
 <html>
  <head>
  <meta http-equiv="Content-Type" 
      content="text/html; charset=UTF-8">
  <title>r4r.co.in-servlet</title>
 </head>
 <body>
  <form>
  <h1>Access Servlet by servlet's Name!</h1>
  <a href="randomValueServlet">randomValueServlet</a>
  </form>
 </body>
</html>

Servlet Program

/*
 * Save as a randomValueServlet.java
 */
package r4r.servlet;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Random;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
/**
 *
 * @author R4R
 */
public class randomValueServlet extends HttpServlet {

//Declare an ArrayList
private ArrayList arrayList = new ArrayList();
private String string = null;

@Override
public void init() throws ServletException {

// Provide Alphabet Range [65- 99]
char ascii[] = new char[100];
for (int i = 0, a = 65; a < 99; a++) {
ascii[i] = (char) a; //Type conversion
i++;
}

// Generate Alphabet [0-26] value and store all into array
System.out.println("Alphabet Generate :\n");
int count = 0;
for (int i = 0; i < 26; i++) {
string = "'" + ascii[count++] + "'" + " ";
arrayList.add(string); // store into array
}
}

protected void processRequest(HttpServletRequest request,
 HttpServletResponse response)throws ServletException,IOException
	{
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
try {
/* TODO output your page here */
out.println("<html>");
out.println("<head>");
out.println("<title>" + getServletInfo() + "</title>");
out.println("</head>");
out.println("<body>");
out.println("<h1>Servlet randomValueServlet at " 
	         + request.getContextPath() + "</h1>");
out.println(" <form name=\"form\" action=\
             "randomValueServlet\" method=\"POST\">");
out.println("<BR><input type=\
         "submit\" value=\"Generate Random Value\" />");
out.println("</form>");
out.println("</body>");
out.println("</html>");
} finally {
out.close();
}
}

@Override
protected void doGet(HttpServletRequest request,
 HttpServletResponse response)throws ServletException,IOException
{
processRequest(request, response);
}

@Override
protected void doPost(HttpServletRequest request,
 HttpServletResponse response)throws ServletException, IOException 
{
response.setContentType("text/html;charset=UTF-8");
PrintWriter out = response.getWriter();
// Print array value [Generated Alphabet] on browser 
out.println
 ("Alphabet Generate :" +"<b>" + arrayList.toString() +"</b>");
        
/*
 * ---------------------------------------------------
 * Method -1: Pick six random alphabet value form List
 * ---------------------------------------------------
 */
int randomValue1 = 
	(0 + (Math.abs(new Random().nextInt())) % arrayList.size());
String string1 =
	(String) arrayList.get(randomValue1);       //Type conversion
int randomValue2 =
	(0 + (Math.abs(new Random().nextInt())) % arrayList.size());
String string2 =
	(String) arrayList.get(randomValue2);
int randomValue3 =
	(0 + (Math.abs(new Random().nextInt())) % arrayList.size());
String string3 = (String) arrayList.get(randomValue3);
int randomValue4 =
	(0 + (Math.abs(new Random().nextInt())) % arrayList.size());
String string4 = (String) arrayList.get(randomValue4);
int randomValue5 =
	(0 + (Math.abs(new Random().nextInt())) % arrayList.size());
String string5 = (String) arrayList.get(randomValue5);
int randomValue6 = 
	(0 + (Math.abs(new Random().nextInt())) % arrayList.size());
String string6 = (String) arrayList.get(randomValue6);
out.println("<BR><BR>Method-1: Six Random Value Pick form List : ");
out.println
	("<b>" + string1 + " " + string2 + " " + string3 +
	" " + string4 + " " + string5 + " " + string6 + "</b>");

/*
 * ---------------------------------------------------
 * Method -2: Pick six random alphabet value form List
 * ---------------------------------------------------
 */
out.println("<BR>Method-2: Six Random Value Pick from List :");
// Shuffle List value and pick six random value form array
Collections.shuffle(arrayList);
for (int i = 0; i < 6; i++) {
String value = (String) arrayList.get(i);
out.println("<b>" + value + "</b>" + " ");
}
out.println
("<BR><BR><a href=\"randomValueServlet\">Generate value again</a>");
out.close();
}

@Override
public String getServletInfo() {
return "r4r.co.in-randomValueServlet";
}
}