ManagedBean method doesn't work in JSF

Question

I have written two managedbean classes named Message and HelloWorld. They are as follow :

Message.java :

package com.bean;

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

@ManagedBean(name = "message", eager = true)
@RequestScoped
@SessionScoped
public class Message {

    private String message = "Hello World!";

    public String getMessage() {
        return message;
    }
    public void setMessage(String message) {
        this.message = message;
    }
}

HelloWorld.java

package com.bean;

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

@ManagedBean(name = "helloWorld")
@RequestScoped
@SessionScoped
public class HelloWorld {

   @ManagedProperty(value="#{message}")
   private Message messageBean;
   private String msg;


   public HelloWorld() {
      System.out.println("HelloWorld started!"); 
   }

   public void setMessage(String message) {
       this.msg = message;
   }

   public String getMessage() {
      if(messageBean != null){
         msg = messageBean.getMessage();
      }       
      return msg;
   }

   public void setMessageBean(Message message) {
      this.messageBean = message;
   }

   public void showMsg(){
      // String str="I am a demo string!";
       System.out.println(msg +" I am from showMsg()");
   }  
}

And, my index.xhtml here:

<body>
    #{helloWorld.message}
    <h:form>
        <h:commandButton value="Show Msg" action="#{helloworld.showMsg}"/>
    </h:form>
</body>

#{helloWorld.message} prints the message perfectly. But the <h:commandButton> does not invoke the methodshowMsg()`. What's the problem?

And you should either use `RequestScope` or `SessionScope` - both together do not make any sense. — dognose, Dec 12 '14 at 15:22
FYI : forthermore, `eager = true` is only applicable to application scoped JSF managed beans. It is as good as it is removed from the `@ManagedBean` annotation. — Tiny, Dec 13 '14 at 03:06

score 4 · Accepted Answer · answered Dec 12 '14 at 15:21

You have used action="#{helloworld.showMsg}" with lowercase w for world. EL is case sensitive. Change to action="#{helloWorld.showMsg}".

Also, what you have been told in the comments, you can't use both @RequestScoped and @SessionScoped, pick one. And, action attribute should resolve to String (showMsg() returns void), it is used to perform navigation. If you just want something done, without navigation, use actionListener instead.

score 1 · Answer 2 · answered Oct 09 '17 at 18:47

1

A ManagedBean annotation doesn't work, if someone accidentally uses a different import, for example javax.annotation.ManagedBean. It must be javax.faces.bean.ManagedBean.

answered Oct 09 '17 at 18:47

Jarekczek

7,456
3
46
66

This is not an answer to this actual problem... It could however show the same behaviour if you make this error. In addition, your 'answer' is in several other Q/A, amongst others: https://stackoverflow.com/questions/15057564/why-are-there-different-bean-management-annotations/15058240 – Kukeltje Oct 09 '17 at 19:12

score 0 · Answer 3 · answered Dec 15 '14 at 15:26

0

EL is case sensitive in jsf. You have used action="#{helloworld.showMsg} with lowercase w and you declare @ManagedBean(name="helloWorld") with uppercase W. Try it, action="#{helloWorld.showMsg}.

answered Dec 15 '14 at 15:26

user3687895

163
4

ManagedBean method doesn't work in JSF

3 Answers3