title: Java Netbeans: 'Package does not exist'
body: <p>I have a problem with my code, even though it hasn't been modified in any way. It just suddenly threw this message. As you can see on the left, that they are all in the correct package, and have correct names.<br>
  What can I do to fix this problem?</p>
  
  <p><a href="https://i.stack.imgur.com/ySp3u.png" rel="noreferrer"><img src="https://i.stack.imgur.com/ySp3u.png" alt="enter image description here"></a></p>