Though you might be finding this post silly but trust me I had to struggle a lot to find this issue in one of my team machine.
We had installed Jdev 11117 and for SOA Extension Plugin, we was having a download zip file, so used that but that caused issue mismatch. Though Jdev did not prompt me any warning for version mismatch but later while using DBAdapter, we found that we were unable to import the table or other things were not working properly.
To fix this issue, we installed the SOA extension plugin from the update which was compatible with Jdev11117.
So my learning is, always download the plugin from updates 🙂