Jettison json conversion not working with arraylist on jboss

Question

I have tried a simple example of a class that has an ArrayList. See below:

class EmployeeList {            

        List<String> departmentNames = new ArrayList<String>();

        public EmployeeList(String dept1, String dept2) {
            super();
            departmentNames.add(dept1);
            departmentNames.add(dept2);
        }

        public String toString()
        {
            return "EMPLOYEELIST DETAILS : " + departmentNames.toString();
        }
    }

Now, I'm trying to convert an ojbect of type EmployeeList into a JSON string, and then back into an object using jettison.

EmployeeList employeeList1 = new EmployeeList("IT","FINANCE");

XStream xstreamWriteEmployeeList = new XStream(new JettisonMappedXmlDriver());
xstreamWriteEmployeeList.alias("employee", EmployeeList.class);

String jsonStringEmployeeList = xstreamWriteEmployeeList.toXML(employeeList1);

XStream xstreamReadEmployeeList = new XStream(new JettisonMappedXmlDriver());

xstreamReadEmployeeList.alias("employee", EmployeeList.class);

EmployeeList employeeList2 = (EmployeeList)xstreamReadEmployeeList.fromXML(jsonStringEmployeeList);

I've tried and it's working on my local system, but when I tried deploying on my application server, it gives an error.

java.lang.NoSuchMethodError: org.codehaus.jettison.AbstractXMLStreamWriter.getSerializedAsArrays()Ljava/util/ArrayList;

Any ideas why? I am using same java version on local system and application server.