Apache Shiro LoginBean class

Apache Shiro LoginBean Class 

package  com.apacheShiro;

import java.io.IOException;

import java.security.MessageDigest;

import javax.faces.application.FacesMessage;
import javax.faces.context.ExternalContext;
import javax.faces.context.FacesContext;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

import oracle.adf.share.logging.ADFLogger;

import org.apache.shiro.SecurityUtils;
import org.apache.shiro.subject.Subject;

import org.apache.shiro.authc.AuthenticationException;
import org.apache.shiro.authc.UsernamePasswordToken;
import org.apache.shiro.web.util.SavedRequest;
import org.apache.shiro.web.util.WebUtils;

public class LoginBean {
 
    private String userName;
    private String password;
    private ADFLogger logger =
    ADFLogger.createADFLogger(LoginBean.class);
    private final String HOME_URL = "/ViewController-context-root/faces/homePage.jsf";

    public void setUserName(String userName) {
        this.userName = userName;
    }

    public String getUserName() {
        return userName;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getPassword() {
        return password;
    }


    public LoginBean() {
    }

    public String login() {
        try {
         
         
            String passwordToHash = password;
                    String generatedPassword = null;
                 
                        // Create MessageDigest instance for MD5
                        MessageDigest md = MessageDigest.getInstance("MD5");
                        //Add password bytes to digest
                        md.update(passwordToHash.getBytes());
                        //Get the hash's bytes
                        byte[] bytes = md.digest();
                        //This bytes[] has bytes in decimal format;
                        //Convert it to hexadecimal format
                        StringBuilder sb = new StringBuilder();
                        for(int i=0; i< bytes.length ;i++)
                        {
                            sb.append(Integer.toString((bytes[i] & 0xff) + 0x100, 16).substring(1));
                        }
                        //Get complete hashed password in hex format
                        generatedPassword = sb.toString();
        // attempt login
        SecurityUtils.getSubject().login(
        new UsernamePasswordToken(userName, generatedPassword));
        // retrieve the saved request
        HttpServletRequest request =
        (HttpServletRequest)(FacesContext.getCurrentInstance().
        getExternalContext().getRequest());
        SavedRequest savedRequest =
        WebUtils.getAndClearSavedRequest(request);
        // get external context in order to redirect
        ExternalContext externalContext =
        FacesContext.getCurrentInstance().getExternalContext();
        if (savedRequest != null) {
        logger.fine("Retrieved saved URL '" +
        savedRequest.getRequestUrl() + "', redirecting");
        externalContext.redirect(savedRequest.getRequestUrl());
        } else {
        logger.fine("No URL retrieved, redirecting to HOME_URL: "
        + HOME_URL);
        externalContext.redirect(HOME_URL);
        }
        } catch (AuthenticationException e) {
        logger.config("Failed login validation for user " +
        userName);
        FacesMessage msg =
        new FacesMessage(FacesMessage.SEVERITY_ERROR,
        "Invalid username/password combination", "");
        FacesContext.getCurrentInstance().addMessage(null, msg);
        } catch (Exception e) {
        logger.warning("Unexpected error during login", e);
        }
        return null;
    }
 
    public String logout() throws ServletException, IOException {
     
        ExternalContext externalContext =
        FacesContext.getCurrentInstance().getExternalContext();
     
        HttpServletRequest request =
        (HttpServletRequest)(FacesContext.getCurrentInstance().
        getExternalContext().getRequest());
        request.getSession().invalidate();
        externalContext.redirect(HOME_URL);
        return null;
    }
}