There should not be the need for the addons folder - instead you can add the source projects to your workspace.
If you want to add binary jars nonetheless, you best add them to your target platform - see here for some documentation on this.
Thank you very much for your response and the link.
Understand can either add them into workspace for developing purpose and target platform for running purpose.
I want to add the prexisting addon jar file org.openhab.ui.habmin_0.1.6.jar (that I downloaded from here) into a working openhab2 in the IDE. I followed these instructions
Window -> Prefernces -> Plug-in Development -> Target Platform shows a Target Platform dialog box with an item selected in bold: openHAB Target Platform (Active) - /launch/openhab.target.
Selected Edit -> (Locations tab) -> Add -> Directory, and added /home/avner/openhab2-master2/ws/tmp1 where I placed the jar file.
After that I’m seeing the habmin jar file (see snapshot)
Following the instructions to execute openhab I see messages in the Console pane, and also http://localhost:8080 responds as expected, but http://localhost:8080/habmin doesn’t come up.
I’m probably importing the habmin jar addon improperly. What should I do to import this jar file into the eclipse, so that it’s taking effect in the project?
Thanks