code: private void validateCompletionListernerForNull(CompletionListener cListener) throws IllegalArgumentException {
  
          if (null == cListener) {
  
              throw (IllegalArgumentException) JmsErrorUtils.newThrowable(
                                                                          IllegalArgumentException.class,
                                                                          "INVALID_VALUE_CWSIA0068",
                                                                          new Object[] { "CompletionListener", null },
                                                                          null,
                                                                          null, // null probeId = no FFDC
                                                                          this,
                                                                          tc);
          }
      }
docs: Validates if CompletionListener is NULL. If it is null throws IllegalArgumentException
  
  @param cListener
  @throws IllegalArgumentException