We would create a portlet for a custom user registration form to register users in Liferay 5.2.2 portal.
In case of empty value form shows an error below the field otherwise, if everything is ok, a message will be shown instead of the form.
When a user completes the registration he will be set not active in the system and he canʼt login in to the portal. Every new registration sends an email to admin to confirm the new registration. The content of the email message will be a liferay web content set by ID in the preferences panel.