jsp:useBean id not clear

[Harikrishna Gorrepati]

Hi, I am not clear how <jsp:useBean> id is working. Here is the complete working code. Can you please explain me how id portion from each file is communicating ?

MurachPage303.jsp

<form action="addToEmailList" method="post">
<jsp:useBean id="user" class="MurachChapter09.User" scope="session" />
First Name:<input type="text" name="firstName" value="<jsp:getProperty name="user" property="firstName"/>"><br>
Last Name: <input type="text" name="lastName"  value="<jsp:getProperty name="user" property="lastName"/>"><br>
E-mail:    <input type="text" name="emailAddress"  value="<jsp:getProperty name="user" property="emailAddress"/>"><br>
<input type="submit" value="submit">
</form>

AddToEmailListServlet.java

package MurachChapter09;

import java.io.IOException;
import java.util.Enumeration;

import javax.servlet.RequestDispatcher;
import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

public class AddToEmailListServlet extends HttpServlet {
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		Enumeration e = request.getParameterNames();
		while(e.hasMoreElements())
			System.out.println(e.nextElement());
		String firstName = request.getParameter("firstName");
		String lastName = request.getParameter("lastName");
		String emailAddress = request.getParameter("emailAddress");

		User user = new User();
		user.setFirstName(firstName);
		user.setLastName(lastName);
		user.setEmailAddress(emailAddress);

		ServletContext sc = getServletContext();
		String path = sc.getRealPath("/WEB-INF/EmailList.txt");
		System.out.println("ServletContext  " + sc);


		HttpSession session = request.getSession();
		session.setAttribute("user", user);

		String URL = "/MurachPage305.jsp";
		RequestDispatcher rd = getServletContext().getRequestDispatcher(URL);
		rd.forward(request, response);
	}
}

User.java

package MurachChapter09;

public class User {
	private String firstName;
	private String lastName;
	private String emailAddress;

	public User() {
		firstName = "";
		lastName = "";
		emailAddress = "";
	}

	public User(String firstName, String lastName, String emailAddress) {
		this.firstName = firstName;
		this.lastName = lastName;
		this.emailAddress = emailAddress;
	}

	public String getFirstName() {
		return firstName;
	}

	public void setFirstName(String firstName) {
		this.firstName = firstName;
	}

	public String getLastName() {
		return lastName;
	}

	public void setLastName(String lastName) {
		this.lastName = lastName;
	}

	public String getEmailAddress() {
		return emailAddress;
	}

	public void setEmailAddress(String emailAddress) {
		this.emailAddress = emailAddress;
	}
}

MurachPage305.jsp

<jsp:useBean id="user" class="MurachChapter09.User" scope="session" />
First Name:<jsp:getProperty name="user" property="firstName"/><br>
Last Name: <jsp:getProperty name="user" property="lastName"/><br>
E-mail:    <jsp:getProperty name="user" property="emailAddress"/><br>
<form action="MurachPage303.jsp" method="post">
To enter other E-mail, Click here..
<input type="submit" value="submit">
</form>

web.xml

	<servlet>
		<servlet-name>AddToEmailListServlet</servlet-name>
		<servlet-class>MurachChapter09.AddToEmailListServlet</servlet-class>
	</servlet>
	<servlet-mapping>
		<servlet-name>AddToEmailListServlet</servlet-name>
		<url-pattern>/addToEmailList</url-pattern>
	</servlet-mapping>

[Bear Bibeault]

The id is the name by which the scoped variable is being bound into the session.