Target Unreachable, identifier resolved to null - read all other questions

Question

I know a lot of questions are already on StackOverflow about this but I have been struggling for over 5 hours now and I just don't know what to do anymore. I hope when someone sees my situation they can point me in the right direction. I think I've tried every single annotation combo and I can't get it to work.

I am setting up a Java EE application, simple web-app. Currently testing my setup in a simple page. The related files are below. The error occurs when pressing on the button on the xhtml page.

javax.el.PropertyNotFoundException: /greeting.xhtml @12,69 action="#{testServlet.createNewUser}": Target Unreachable, identifier 'testServlet' resolved to null

greeting.xhtml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
    "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml"
      xmlns:h="http://xmlns.jcp.org/jsf/html">
    <h:head>
        <title>Test Page</title>
    </h:head>
    <h:body>
        <h:form>
            <h:commandButton value="Go"
                             action="#{testServlet.createNewUser}"/>
        </h:form>

    </h:body>
</html>

TestServlet.java

package kwetter.admin.test;

import java.io.Serializable;
import javax.enterprise.context.SessionScoped;
import javax.inject.Inject;
import javax.inject.Named;
import kwetter.domain.entities.User;
import kwetter.logic.beans.TestBean;

@Named
@SessionScoped
public class TestServlet implements Serializable {

    @Inject
    private TestBean testBean;

    public TestServlet() {
        System.out.println("TEST CREATED ");
    }

    public String createNewUser() {
        User user = new User();
        testBean.createUser(user);

        return "cool";
    }

}

TestBean.java

package kwetter.logic.beans;

import java.io.Serializable;
import javax.ejb.EJB;
import javax.ejb.Stateless;
import kwetter.database.daos.interfaces.IUserDao;
import kwetter.domain.entities.User;

@Stateless
public class TestBean implements Serializable
{

    @EJB
    private IUserDao userDao;

    public TestBean() {

    }

    public boolean createUser(User user) {
        userDao.save(user);
        return true;
    }
}

IUserDao declaration

public interface IUserDao extends IDao<User>

And the implemenatation:

@Stateless
public class UserDao implements IUserDao

Dependencies of the different modules are handled in the pom files. Example part of the pom:

    <dependency>
        <groupId>com.woutervanacht.kwetter</groupId>
        <artifactId>logic</artifactId>
        <version>1.0-SNAPSHOT</version>
        <scope>provided</scope>
    </dependency>

Other:

I have an empty beans.xml in WEB-INF (not sure if this is needed anymore, started without and read it a couple of times
faces-config.xml which has no childs in the root element
web.xml with servlet mapping.

I don't want to clutter this question with too much information. If you need anything that is relevant I'll happily share.

Thanks in advance for thinking with me.

have you tried the steps described at: https://stackoverflow.com/questions/30128395/identifying-and-solving-javax-el-propertynotfoundexception-target-unreachable ? 1st section at CDI managed bean... — , Feb 22 '19 at 09:52
@nikolairiedel Yes. The only related bullet to my situation would be the third of the CDI part (since I'm using `@Named`). I checked the import and it is correctly the CDI one. — Wouter van Acht, Feb 22 '19 at 09:55

score 1 · Answer 1 · answered Feb 22 '19 at 10:19

Judging from this github issue: https://github.com/javaserverfaces/mojarra/issues/4264

you have two options.

1) Add FacesConfig Annotation to your beans and explicitly declare the JSF version:

@FacesConfig(
    // Activates CDI build-in beans
    version = JSF_2_3
)

So that would give you for your TestServlet.java:

package kwetter.admin.test;

import java.io.Serializable;
import javax.enterprise.context.SessionScoped;
import javax.inject.Inject;
import javax.inject.Named;
import kwetter.domain.entities.User;
import kwetter.logic.beans.TestBean;

@FacesConfig(
    // Activates CDI build-in beans
    version = JSF_2_3
)
@Named
@SessionScoped
public class TestServlet implements Serializable {

    @Inject
    private TestBean testBean;

    public TestServlet() {
        System.out.println("TEST CREATED ");
    }

    public String createNewUser() {
        User user = new User();
        testBean.createUser(user);

        return "cool";
    }
}

With your empty WEB-INF/beans.xml you are in bean-discovery-mode annotated and this does not seem to work as described in the issue above. More Info on the bean-discovery-mode can be found here: https://blogs.oracle.com/theaquarium/default-cdi-enablement-in-java-ee-7.

2) Set bean-discover-mode to all in the beans.xml

So that would give you

<?xml version="1.0" encoding="UTF-8"?>

<beans xmlns="http://xmlns.jcp.org/xml/ns/javaee"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/beans_1_1.xsd"
       version="1.1" bean-discovery-mode="all">
</beans>

I think 1 is the most reasonable solution, as it kinds of contains the problem. On the other side you'll probably have the same problem with the other beans.

I already tried your second approach because I stumbled upon it when googling for countless hours. I tried your first solution but this doesn't seem to do anything either. Thanks for thinking with me anyway. — Wouter van Acht, Feb 22 '19 at 10:28
Alright so I found something when copying stuff 'that worked' from the GitHub issue: The problem is with my `@Inject TestBean testBean;`. Whenever I comment that out a simple `getOutput()` function works. But with it enabled it just doesn't get called. — Wouter van Acht, Feb 22 '19 at 10:59

Target Unreachable, identifier resolved to null - read all other questions

1 Answers1