code: @Override
      public Namespace createNamespace(Namespace namespace) {
          requireNotDisposed();
          requireArgument(namespace != null, "null namespace cannot be created.");
          
          if (!_validateQualifier(namespace.getQualifier())) {
              throw new SystemException(new IllegalArgumentException(
                      "Illegal characters found while generating namespace. Cannot generate a namespace with this qualifier."));
          }
          
          if (Namespace.findByQualifier(emf.get(), namespace.getQualifier()) != null) {
              throw new SystemException(new IllegalArgumentException("Namespace already exists. Please try a different namespace."));
          }
          
          namespace = updateNamespace(namespace);
          _logger.debug("Generated namespace {}.", namespace);
          return namespace;
      }
docs: Creates a new namespace.
  
  @param   namespace  The namespace to create.  Cannot be null.
  
  @return  The updated namespace object having the ID field populated.
  
  @throws  SystemException  If a duplicate namespace exists.