code: @Override
      public void setPersistentMapping(String persistentMapping) throws JMSException {
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled())
              SibTr.entry(this, tc, "setPersistentMapping", persistentMapping);
  
          if (persistentMapping == null) {
              throw (JMSException) JmsErrorUtils.newThrowable(
                                                              JMSException.class,
                                                              "INVALID_VALUE_CWSIA0261",
                                                              new Object[] { "persistentMapping", null },
                                                              tc
                              );
          }
  
          if (persistentMapping.equals(ApiJmsConstants.MAPPING_BEST_EFFORT_NONPERSISTENT) ||
              persistentMapping.equals(ApiJmsConstants.MAPPING_EXPRESS_NONPERSISTENT) ||
              persistentMapping.equals(ApiJmsConstants.MAPPING_RELIABLE_NONPERSISTENT) ||
              persistentMapping.equals(ApiJmsConstants.MAPPING_RELIABLE_PERSISTENT) ||
              persistentMapping.equals(ApiJmsConstants.MAPPING_ASSURED_PERSISTENT) ||
              persistentMapping.equals(ApiJmsConstants.MAPPING_NONE)) {
              jcaManagedConnectionFactory.setPersistentMapping(persistentMapping);
          }
          else if (persistentMapping.equals(ApiJmsConstants.MAPPING_AS_SIB_DESTINATION)) {
              jcaManagedConnectionFactory.setPersistentMapping(ApiJmsConstants.MAPPING_NONE);
          }
          else {
              throw (JMSException) JmsErrorUtils.newThrowable(
                                                              JMSException.class,
                                                              "INVALID_VALUE_CWSIA0261",
                                                              new Object[] { "persistentMapping", persistentMapping },
                                                              tc
                              );
          }
  
          if (TraceComponent.isAnyTracingEnabled() && tc.isEntryEnabled())
              SibTr.exit(this, tc, "setPersistentMapping");
      }
docs: default persistent mapping is RELIABLE_PERSISTENT, null persistent mapping is
  not valid.