Command
originate {foo=bar}sofia/gateway/gizmo1/848458448557 121

Dial Plan
      <extension name="java_test" continue="true">
          <condition field="destination_number" expression="121">
              <action application="java" data="/home/adeel/programs/freeswitch/scripts/freeswitch.jar net.digitalapps.freeswitch.CallTest abcdefgh ${foo}"/>
          </condition>
      </extension>