Suggested by Sten Baumgarten – Under Review
In platform update 6 it is possible to import lines into a general journal, but it is only possible to import main account and not financial dimension values that must be included before the journal can be posted.
Customization are described by Microsoft, but instead of making the customization, I will prefer that the functionality are included in the standard solution.
Status Details
Hello, thank you for the suggestion. This is definitely in our goal to allow this without having to do a customization. We are working on a technical approach. Please watch our roadmap site for details. I appreciate the feedback. Sincerely, April

In platform update 4 as well , it is possible to import lines into gj by setting up Financial dimension configuration for integrating application in system . Make the template as active and import via excel.