title: Only unknown data type in SQLDeveloper
body: <p>I have been using SQLDeveloper a while and I made a schema in it. But now, for some reason, when I open this schema, all the data types are set to "unknown".</p>
  
  <p>When I open a new schema and create an entity, I only have 'unknown' option for logical data type, nothing else.</p>
  
  <p>I am not aware of changing anything, so I am lost. Has anyone encountered anything like this?
  <em>(in kubuntu, I can't take a screenshot of a dropdown menu, for some reason, but it contains only one value - unknown)</em>
  <img src="https://i.stack.imgur.com/R4zRk.png" alt="enter image description here"></p>