Because of the extension mechanism for portal containers, changing the context path  of GateIn requires to modify several files.

By default, the main portal container is accessible at http://localhost:8080/portal we want to change that URL to:

http://localhost:8080/myportal

Modify the context path, by editing gatein.ear/META-INF/application.xml

<module>
  <web>
    <web-uri>02portal.war</web-uri>
    <context-root>myportal</context-root>
  </web>
</module>

Now you need to use the same String for the 02portal.war display name. Edit gatein.ear/02portal.war/WEB-INF/web.xml

<display-name>myportal</display-name>

You will also need to specify the name of the portal container to match that key, to do so edit:

$JBOSS_HOME/server/default/conf/gatein/configuration.xml

And change the following:

<value-param>
  <name>default.portal.container</name>
  <value>myportal</value>
</value-param>

<authentication>
  <login-module code="org.exoplatform.web.security.PortalLoginModule" flag="required">
    <module-option name="portalContainerName">myportal</module-option>
    <module-option name="realmName">gatein-domain</module-option>
  </login-module>
  <login-module code="org.exoplatform.services.security.jaas.SharedStateLoginModule" flag="required">
    <module-option name="portalContainerName">myportal</module-option>
    <module-option name="realmName">gatein-domain</module-option>
  </login-module>
  <login-module code="org.exoplatform.services.security.j2ee.JbossLoginModule" flag="required">
    <module-option name="portalContainerName">myportal</module-option>
    <module-option name="realmName">gatein-domain</module-option>
  </login-module>
</authentication>