xml files shouldnt depend on external web servers, are they?

When I search for schemaLocation="http in the Grouper/PSP source I see a lot of matches that look like this:

xsi:schemaLocation="http://www.springframework.org/schema/beans classpath:/schema/spring-beans-2.5.xsd
http://www.springframework.org/schema/util classpath:/schema/spring-util-2.5.xsd">

Or even in poms:

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">

Is there a way to refer to xsd internally?