What you need is to setup your application's entry point. For this you need to configure your main class inside the jar's Manifest file.
Something like
Manifest-Version: 1.0.1
Created-By: <jdk_version>
Main-Class: fully.qalified.class.name.with.main.method
For more details on Manifest, take a look into this link here
For making this step part of your maven build cycle, you need to make some changes in the mave.jar.plugin. Something like
<plugin>
<groupId>org.apache.maven.plugins</groupId>
<artifactId>maven-jar-plugin</artifactId>
<version>2.4</version>
<configuration>
<archive>
<manifest>
<mainClass>fully.qalified.class.name.with.main.method</mainClass>
</manifest>
</archive>
</configuration>
</plugin>
The final jar that is created will have your main method as the applications entry point