The code you have provided from Roo is a little unnecessary. If you look at the Spring MVC documentation as tkeE2036 pointed out... you will see the themes section http://static.springsource.org/spring/docs/3.0.x/spring-framework-reference/html/mvc.html#mvc-themeresolver
<link rel="stylesheet" href="<spring:theme code='styleSheet'/>" type="text/css"/>
The Spring theme tag gives you the ability to internationalize your CSS/images/js (imagine an image that has the word 'Hello' which needs to be changed for English/Spanish/etc) into separate internationalized theme files that follow the http://java.sun.com/javase/6/docs/api/java/util/ResourceBundle.html convention and Spring will automatically resolve the correct resource bundled theme.
If you still want your ${imagePath} or whatever, you can use the <spring:url/> tag to get your job done.
<spring:url value="/images" var="imagePath"/>
<link rel="stylesheet" href="${imagePath}/foo.png" type="text/css"/>