title: cannot resole file in <sourceDirectory>src/main/java</sourceDirectory> in pom file of spring boot app
body: <p>in this spring boot back-end project, the ide gives an error which says "cannot resolve file in  <strong>src/main/java</strong>"
  how to fix this error
  thanks in advance</p>
  
  <p><a href="https://i.stack.imgur.com/bMkH2.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/bMkH2.png" alt="cannot resole file in  &lt;sourceDirectory&gt;src/main/java&lt;/sourceDirectory&gt;"></a></p>