For developer convenience, working on topic branch and pushing topic branch to team repository:
https://bitbucket.org/lorainelab/experimental-apps-for-igb/branch/IGBF-2213

Note: When topic branch is merged, will close it.

Made some progress, but it still does not work.
Call to NCBI service is being made incorrectly somehow. I added some notes on this to the code. Also, I moved some testing code from "main" into "test" and add junit imports and Test annotations. Also added notes as to what I think needs to be done next.
I am not sure if the App can be fixed. The next step would be to find out why it is not working. Once we know that, we can determine if it is possible to fix it. One concern I have is that the code seems to assume that the primer design will happen quickly, which may have been the case in the past but does not appear to be currently. What happens is that that a job gets submitted and then you have to wait 30 seconds to a minute or more for it to complete. In the meantime, you get back a URL with a job ID. This is similar to how the InterproScan web service works (see ProtAnnot App). If the waiting period is long, then we need to run the search in a separate thread so that IGB does not block. Also, we might want to change the UI so that a user can observe the progress, similar to how ProtAnnot works. Last but not least, we should probably use more modern tooling to send the POST request to the NCBI server.
That's all I've got for now! Closing this issue for the moment.

I did some additional work on this and have committed a partial fix.