title: Java package does not exist after library import
body: <p>I added a jar library to the project that contains the package, but it doesn't recognize that. Why do I get the error? And how do I fix it?</p>
  
  <p>Screenshot:</p>
  
  <p><a href="https://i.stack.imgur.com/lj29b.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/lj29b.png" alt="Screenshot_1"></a></p>
  
  <p><sub>Click to enlarge</sub></p>