JSF 2.2.1，后备bean无法绑定到xhtml页面

Question

I'm trying to develop a simple Jsf 2.2.1 application. I have looked through some pages and found sample applications. I wanted to try one of those samples. I set every dependencies and annotations; however, the backing bean is not working. What I wanted to do is to show some text fields via bean on the Jsf page and render some input texts. Jsf tags are working correctly but the bean values are not shown on the page. In the page I have an input text area and a command button. These components are shown on the page but I feed some text and press the command button I encounter the following problem. I am building the app with "mvn clean package" and then deploying it on Tomcat 7.x.

Error:

serverError: class javax.el.PropertyNotFoundException Target Unreachable, identifier 'helloWorld' resolved to null

In the followings I am sharing all my files.

web.xml:

<?xml version="1.0" encoding="UTF-8"?>
<web-app id="WebApp_ID" version="2.5"
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_2_5.xsd">
<display-name>helloworld</display-name>
<welcome-file-list>
    <welcome-file>home.xhtml</welcome-file>
</welcome-file-list>
<servlet>
    <servlet-name>Faces Servlet</servlet-name>
    <servlet-class>javax.faces.webapp.FacesServlet</servlet-class>
    <load-on-startup>1</load-on-startup>
</servlet>

<servlet-mapping>
    <servlet-name>Faces Servlet</servlet-name>
    <url-pattern>*.xhtml</url-pattern>
</servlet-mapping>
<context-param>
    <param-name>javax.faces.PROJECT_STAGE</param-name>
    <param-value>Development</param-value>
</context-param>

pom.xml:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.test</groupId>
<artifactId>helloworld</artifactId>
<packaging>war</packaging>
<version>1.0-SNAPSHOT</version>
<name>helloworld Maven Webapp</name>
<url>http://maven.apache.org</url>
<dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>3.8.1</version>
      <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>com.sun.faces</groupId>
        <artifactId>jsf-api</artifactId>
        <version>2.2.1</version>
        <scope>compile</scope>
    </dependency>
    <dependency>
        <groupId>com.sun.faces</groupId>
        <artifactId>jsf-impl</artifactId>
        <version>2.2.1</version>
        <scope>compile</scope>
    </dependency>
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>jstl</artifactId>
        <version>1.2</version>
    </dependency>
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>servlet-api</artifactId>
        <version>2.5</version>
    </dependency>
            <dependency>
        <groupId>javax.el</groupId>
        <artifactId>el-api</artifactId>
        <version>2.2</version>
        <scope>provided</scope>
    </dependency>
    <dependency>
        <groupId>org.glassfish.web</groupId>
        <artifactId>el-impl</artifactId>
        <version>2.2</version>
        <scope>provided</scope>
    </dependency>
</dependencies>

<build>
    <finalName>helloworld</finalName>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>2.3.1</version>
            <configuration>
                <source>1.5</source>
                <target>1.5</target>
            </configuration>
        </plugin>

    </plugins>
</build>
<repositories>
    <repository>
        <id>maven2-repository.dev.java.net</id>
        <name>java.net Repository for Maven</name>
        <url>http://download.java.net/maven/2</url>
    </repository>
</repositories>

Java Beans: HelloWorld.java

import javax.faces.bean.ManagedBean;
import javax.faces.bean.ManagedProperty;
import javax.faces.bean.SessionScoped;

@ManagedBean(name="helloWorld")
@SessionScoped
public class HelloWorld {
private String name="Zaman Safari";
@ManagedProperty(value = "#{demoService}")
private Service service;
public HelloWorld(){
    System.out.println("HELLOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO");
}
public String getName(){
    return name;
}

public void setName(String name){
    this.name = name;
}

public void setService(Service service){
    this.service = service;
}

public String getReverse(){
    return service.reverse(name);
}
}

Service.java:

import javax.faces.bean.ApplicationScoped;
import javax.faces.bean.ManagedBean;

@ManagedBean(name="demoService")
@ApplicationScoped
public class Service {

public String reverse(String name) {
    return new StringBuffer(name).reverse().toString().toLowerCase();
}
}

What exactly am I missing in my files?

Answer 1

PropertyNotFoundException mean there is no getter/setter property method in your backing bean.

HelloWorldBean.java

@ManagedBean(name="HelloWorldBean")
public calss HelloWorldBean {

    private String getHelloWorld() {
        return "Hello World!";
    }
}

mypage

    <h:outputText value="#{HelloWorldBean.helloWorld}"/>