I had the same problem with eclipse. I still get a warning ("No grammar costraints..)
But the application works.
this is my faces-config file:
<?xml version="1.0" encoding="UTF-8"?>
<faces-config
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/web-facesconfig_2_2.xsd"
version="2.2">
<application>
<action-listener>org.primefaces.application.DialogActionListener</action- listener>
<navigation-handler>org.primefaces.application.DialogNavigationHandler</navigation-handler>
<view-handler>org.primefaces.application.DialogViewHandler</view-handler>
<locale-config>
<default-locale>de</default-locale>
<supported-locale>en</supported-locale>
</locale-config>
<resource-bundle>
<base-name>Messages</base-name>
<var>msg</var>
</resource-bundle>
</application>
</faces-config>
Messages is the base file names for the properties.The files are called Messages.properties (default) and Messages_de.properties.