I have a project babybird which has 3 components persistence, business and service

in babybird's pom.xml I have following 

   <modules>
        <module>persistence</module>
        <module>business</module>
        <module>service</module>
    </modules>

when I run mvn clean install, I see 

[INFO] ------------------------------------------------------------------------
[INFO] Reactor Summary:
[INFO] 
[INFO] babybird  ......................................... SUCCESS [2.801s]
[INFO] persistence ....................................... SUCCESS [3.321s]
[INFO] business .......................................... SUCCESS [0.832s]
[INFO] service ........................................... SUCCESS [0.694s]
[INFO] ------------------------------------------------------------------------
[INFO] BUILD SUCCESS
[INFO] ------------------------------------------------------------------------
[INFO] Total time: 8.168s
[INFO] Finished at: Tue Jan 22 12:09:48 PST 2013
[INFO] Final Memory: 18M/50M
[INFO] ------------------------------------------------------------------------

and each one of these modules generate a jar file.

Question: How can I combine them into one babybird.war?
I am new to Maven and do not know what to look for to accomplish this task, please provide the pointers

java maven
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