What you are describing sounds very similar to the Tiles experience, which is growing in popularity and flexibility over widgets.
It sounds like you've tried the Java SDK w/Jersey, but without success. Could you share some light as to some of the problems? When it comes to Tiles, it does quite well. You'll probably want to use a service like Local Jive Add-On Development in the Cloud using ngrok to help with development. Assuming your instance if Jive 7 or higher?
Let us know, and sorry for the delay.
Thank you for the reply. I have been trying to utilize the Java SDK and posted my results in this thread Announcing the Jive SDK (Java) Jersey Edition on GitHub Open Source. Currently mine is the last comment.
BTW I am on Jive Cloud so version 8.0 8c4