iText is a Java based API used to manipulate PDF documents.
Using this API, you can extract attachments from within LiveCycle.
But I used the Service Operation 'processFormSubmission' to retrieve the list of attachments.
Variable Name: 'CONTENT_TYPE'
In the 'Additional Output' section, there is a output parameter 'Attachments' for us to set the List (document) variable.
you can also use executeScript DSC to write a code to extract attachments.
Make a process variable of type "list" and subtype "document".
And then use patExecContext.getProcessDataListValue() method to get all the attachments.
and if you need to extract file extension of that attachment then you can use "wsfilename" attribute.