Description: Limited to code that overrides a form's submit functionality, for example to add additional validation. You can also use this extension type for the following after-commit actions:
Displaying a message in the UI.
Sending a message to an external system
Sending an email
Updating a custom table for success scenarios, where the update is not part of core business functionality.
Code extensions of this type are only available for platform-neutral forms. To find out whether an existing N4 form or view is platform-neutral, click the info button 
for the form or table. A view-only form opens, showing the variform code definition. The first line in platform-neutral forms is: "NOTE: This form view supports form submission code extension." For a table, a line similar to the following in the top section (usually the second or the third line from the top) indicates that it is platform-neutral: "Table Shared UI Manager: com.navis.carina.announcement.presentation.AnnouncementSharedUiTableManager@40bef321".
Abstract Base Class: AbstractFormSubmissionCommand
Interface: EFormSubmissionCommand
Module: Framework
Version Added: 2.2
Requires Code Extension Name or Name Pattern: No
Code Extension Name or Name Pattern: N/A
Where to specify code extensions of this type: After creating a code extension of this type, you need to add it to the form whose submit functionality you want to override, as follows, where the name is the name of the code extension:
<form id="A_FORM_ID"/>
...
<formSubmissionCodeExtension name="aFormSubmissionCodeExtension"/>
....
</form>
N4 invokes the code extension whenever a user clicks Save in the respective form.