Target Unreachable, identifier "demoBean" resolved to null

I am developing a web application using JSF on Netbeans 7.0. I have created 2 pages: one for entering persons name and other to display that name. I am using a java bean with get and set methods.

I get an error when I submit my form on first page the code.

This is my first page index.xhtml to accept name:

<h:form>

    Enter your Name : <h:inputText value="#{demoBean.name}" required="true"/>

    <br/> <h:commandButton value="Submit" action="welcome.xhtml"/>    

</h:form>

This is the other page welcome.xhtml to display the name:

<h:body>

    Hello #{demoBean.name}

</h:body>

This is the managed bean demoBean.java :

import javax.faces.bean.ManagedBean; 

import javax.faces.bean.SessionScoped; 



@ManagedBean()

@SessionScoped



public class demoBean {

    private String name;



    public String getName() {

        return name;

    }



    public void setName(String name) {

        this.name = name;

    }

}

This is the error which I got when I submit the fist page:

/index.xhtml @10,86 value="#{demoBean.name}": Target Unreachable, identifier 'demoBean'

resolved to null