If you use the XMLSerializer
from net.sf.json-lib
you have to bring the optional XOM dependency as well otherwise execution will fail.
Use:
<dependency>
<groupId>net.sf.json-lib</groupId>
<artifactId>json-lib</artifactId>
<version>2.4</version>
<classifier>jdk15</classifier>
</dependency>
<dependency>
<groupId>xom</groupId>
<artifactId>xom</artifactId>
<version>1.1</version>
</dependency>