Setting up JNDI with a Tomcat 7 environment using Liferay 6.1

I'm very confused why this isn't working. The environment is a Liferay 6.1 instance with Tomcat 7 and the database is NOT the default database from Liferay. It's a secondary server that is used for data. So I'm not sure if that matters with Liferay or not.

web.xml (located in webapps/conf in Tomcat)

<web-app>...
<resource-ref>
    <description>My database</description>
    <res-ref-name>jdbc/xxx</res-ref-name>
    <res-type>javax.sql.DataSource</res-type>
    <res-auth>Container</res-auth>
</resource-ref>
</web-app>

server.xml (located in webapps/conf in Tomcat)

<GlobalNamingResources>
<Resource name="jdbc/xxx" auth="Container" type="javax.sql.DataSource" username="a" password="y" driverClassName="com.mysql.jdbc.Driver" url="jdbc:mysql://localhost:3306/xxx" 
    maxActive="200" maxIdle="25" />
</GlobalNamingResources>

context.xml (located in webapps/conf in Tomcat)

<context>
    <ResourceLink global="jdbc/xxx" name="jdbc/xxx" type="javax.sql.DataSource" />
</context>

Code:

        Context ctx = new InitialContext();
        DataSource ds = (DataSource)ctx.lookup("java:comp/env/jdbc/xxx");
        Connection conn = ds.getConnection();

Error:

2016-12-21 19:13:04 FATAL asdasdsd:128 - Exception thrown in (removed): 
javax.naming.NameNotFoundException: Name [java:comp/env/jdbc/xxx] is not bound in this Context. Unable to find [java:comp].
    at org.apache.naming.NamingContext.lookup(NamingContext.java:820)
    at org.apache.naming.NamingContext.lookup(NamingContext.java:168)

What am I missing?

Edit:

Also confirmed the following:

mysql connector is in the path
same jar is in the classpath of the portlet

Second Edit:

I created a brand new, fresh dynamic web application project with the same configuration and DAO layer and it worked 100%. I have a feeling it's related to Liferay now. Unfortunately..

Third Edit:

Tried everything, including this article: http://www.journaldev.com/2513/tomcat-datasource-jndi-example-java

This didn't work either. Same exception. The lack of information about this issue on the Liferay website is amazing to me. Documentation appears to be very much lacking.

Solution

For anyone that this helps in the future, because boy was this a pain and not well documented.

I had to add this to the portlet-ext.properties of the Liferay application:

portal.security.manager.strategy=none

Once I found this link: Liferay/Tomcat "hot-deploy" closes JNDI connection, how can I keep it open?

It ended up solving my problem.