How to set the name of a form without a class?

Question

Here is written how to set the name of a form with a class:

http://symfony.com/doc/2.0/book/forms.html#creating-form-classes

but how to set the name of this

Answer 1

If you're using Symfony 3.1, the field types have changed to use their explicit class (FormType, TextType, and EmailType) and the parameter position for the value of the form name attribute has switched places with the FormType parameter in the createNamedBuilder function.

$this->get('form.factory')
  ->createNamedBuilder('form_name', FormType::class, $defaultData)
  ->add('name', TextType::class)
  ->add('email', EmailType::class)
  ->getForm();