How to install and use CDI on Tomcat?

I'm creating my first project Java EE 7, but I'm having trouble. Appreciate any help.

Tomcat 7.0.34
JSF 2.2
Primefaces 3.5
javaee-api-7.0.jar

When the application start, the Tomcat log shows the following message:

"validateJarFile (C:\...\build\web\WEB-INF\lib\javaee-api-7.0.jar)-jar not loaded. See Servlet 2.3 Spec, section 9.7.2. Offending class: javax/servlet/Servlet .class"

when I click on the button that calls the managed bean, I get the error:

Advertência: /index.xhtml @18,66 value="#{indexMB.user}": Target Unreachable, identifier 'indexMB' resolved to null
javax.el.PropertyNotFoundException: /index.xhtml @18,66 value="#{indexMB.user}": Target Unreachable, identifier 'indexMB' resolved to null

IndexMB

@Named("indexMB")
@RequestScoped
public class IndexMB {

private String password;
private String user;

public String loginTest(){
    return (this.user.equals("admin") ? "adminPage" : "inOutPage");
}

// getters and setters
}

index.xhtml

<html ...>

<f:loadBundle basename="i18n" var="bundle" />
<h:head>
    <title>#{bundle['index_title']}</title>
</h:head>
<h:body>
    #{bundle['index_appname']}
    <br />
    <h:form id="frmIndex">
        <p:panelGrid columns="2">
            <p:outputLabel for="user" value="#{bundle['lblUser']}" />
            <p:inputText id="user" value="#{indexMB.user}" />

            <p:outputLabel for="password" value="#{bundle['lblPassword']}" />
            <p:password id="password" value="#{indexMB.password}" />
        </p:panelGrid>
        <p:commandButton action="#{indexMB.loginTest}" value="#{bundle['btn_login']}" />
    </h:form> 
</h:body>

faces-config.xml

<?xml version='1.0' encoding='UTF-8'?>
<faces-config version="2.2"
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/web-facesconfig_2_2.xsd">

<application>
    <locale-config>
        <default-locale>pt_BR</default-locale>
        <supported-locale>en</supported-locale>
        <supported-locale>fr</supported-locale>
    </locale-config>
</application>

These topics have not helped me:

Solution

Tomcat as being a barebones JSP/Servlet container doesn't support CDI out the box. It is not correct to drop jakartaee-api.jar or javaee-api.jar in /WEB-INF/lib just to get your code to compile. The JEE API JAR contains solely the API classes, not the concrete implementation. Get rid of the whole JAR. It can cause many other portability troubles like as the ones described in this answer: How do I import the javax.servlet / jakarta.servlet API in my Eclipse project? You should actually be installing the concrete implementation along with the specific API.

You have 2 options:

Drop Tomcat and go for a true Jakarta EE container. As you're using Tomcat, just step over to TomEE. It's really simple, download the TomEE web profile zip file, extract it and integrate it in Eclipse exactly the same way as you did for Tomcat. Don't forget to remove the Jakarta EE JAR file from webapp and alter the Targeted Runtime property in project's properties from Tomcat to TomEE so that Jakarta EE dependencies are properly resolved. See also What exactly is Java EE?

No additional JARs or configuration is necessary. You can even remove the manually installed JSF/JSTL/CDI/BV/JPA/EJB/JTA/JSONPJAX-RS/etc/etc libraries from your webapp. TomEE as being a true Jakarta EE container already provides them all out the box. In case you're using Maven, the below coordinate is sufficient.
```
 <dependency>
     <groupId>jakarta.platform</groupId>
     <artifactId>jakarta.jakartaee-web-api</artifactId>
     <version></version>
     <scope>provided</scope>
 </dependency>
```
Note the importance of provided and its meaning as in "the target runtime already provides this out the box". See also How to properly configure Jakarta EE libraries in Maven pom.xml for Tomcat? for detailed pom.xml examples of Tomcat and normal JEE containers.
If you want to stick to Tomcat, then you need to manually install a true CDI implementation via the webapp. Below instructions assume Tomcat 10+. Weld is one of the available CDI implementations. In the Weld installation guide you can find instructions how to integrate it in Tomcat. For sake of completeness and future reference, here are the steps:
1. For Tomcat 11.x, drop the weld-servlet-shaded.jar of version 6.x (currently still beta) in webapp's /WEB-INF/lib. In case you're using Maven, use this coordinate:
```
 <dependency>
     <groupId>org.jboss.weld.servlet</groupId>
     <artifactId>weld-servlet-shaded</artifactId>
     <version>6.0.0.Beta4</version>
 </dependency>
```
  For Tomcat 10.1.x, drop the weld-servlet-shaded.jar of version 5.x in webapp's /WEB-INF/lib. In case you're using Maven, use this coordinate:
```
 <dependency>
     <groupId>org.jboss.weld.servlet</groupId>
     <artifactId>weld-servlet-shaded</artifactId>
     <version>5.1.3.Final</version>
 </dependency>
```
  For Tomcat 10.x, use weld-servlet-shaded.jar of version 4.x instead:
```
 <dependency>
     <groupId>org.jboss.weld.servlet</groupId>
     <artifactId>weld-servlet-shaded</artifactId>
     <version>4.0.3.Final</version>
 </dependency>
```
2. Optionally, create a /META-INF/context.xml file in webapp with following content:
```
 <Context>
     <Resource name="BeanManager" 
         auth="Container"
         type="jakarta.enterprise.inject.spi.BeanManager"
         factory="org.jboss.weld.resources.ManagerObjectFactory"/>
 </Context>
```
  This step is is only necessary when the CDI-dependent library tries to manually find it in JNDI. This step is not necessary when you're using for example Jakarta Faces / JSF version 2.3 or newer.
3. Create a /WEB-INF/beans.xml file in webapp to trigger activation of CDI. It can be kept empty.
That's it.

In case you prefer OpenWebBeans above Weld as CDI implementation, or need to install CDI in Tomcat 9.x or older, head to this blog for detailed Maven installation instructions: How to install CDI in Tomcat?