Resolution:
It is not recommended to call custom java code from the workflow.

Usually in the field, java code will be called from a transition of the workflow through the Condition element as follows (eg):

       &ltCondition format="bsh"><![CDATA[
                        result = (eventid != null);
                if (result)
                {
                    System.out.println("========= Start Import : Call SP======");
                                              java.sql.Connection conn = com.martquest.util.DBUtil.getConnection();
                    //com.cim.plugin.PostProcessor.postProcess(conn, hm);
                                             com.martquest.util.DBUtil.closeConnection(conn);
                    System.out.println("Returned from SP Call ===================");
                }
                ]]></Condition>