maven-jawr-plugin is a maven plugin for the https://jawr.dev.java.net/ project
(that among other things does bundling and compressing of javascript and CSS)

Read https://jawr.dev.java.net/docs/descriptor_syntax.html for what your
jaws.properties file can include. Since (with this maven plugin )you'll
be dealing with static files, you'll probably have no need for the
cssurlrewrite post processor (+ it can mess the cssimport processor) - so, 
just disable it with:
jawr.css.bundle.factory.filepostprocessors=none


Simple usage (add inside the <build> tag of your pom.xml):

    <plugin>
        <groupId>org.amplafi.jawr</groupId>
        <artifactId>maven-jawr-plugin</artifactId>
        <version>0.5-SNAPSHOT</version>
        <executions>
          <execution>
            <!-- Use this phase so that maven war includes our bundles -->
            <phase>process-resources</phase>
            <goals>
              <goal>bundle</goal>
            </goals>
          </execution>
        </executions>
        <configuration>
            <configLocation>src/main/resources/jaws.properties</configLocation>
            <bundles>
                <bundle>/css/bundle-member.css</bundle>
                <bundle>/css/bundle-guest.css</bundle>
            </bundles>
        </configuration>
    </plugin>

Finally, an alternative way of getting the plugin (instead of building and installing
it from source) is by adding this repository in your pom.xml:

    <repository>
        <id>tacos-snapshot-repo</id>
        <name>Tacos Snapshot Repo</name>
        <url>http://tacos.sourceforge.net/nightly/</url>
    </repository>