title: Exporting Java project as .jar file will complain that certain .java files aren't found
body: <p>When trying to export a project as a <code>.jar</code> file, Eclipse will complain that some files can't be found on the classpath:</p>
  
  <blockquote>
    <p>Class files on classpath not found or not accessible for: 'proj/src/main/java/analysis/specification/VerifyVariableIsDefinedInsideTargetTerm.java'</p>
  </blockquote>
  
  <p>Now, the interesting part is that these files haven't actually existed on the disk for ages. I guess I force Eclipse to refresh its database some way. I've tried doing F5 for a full build, but it seems to no avail. I've also tried the procedure described in <a href="http://blog.timmattison.com/archives/2009/11/10/how-to-fix-a-broken-eclipse-environment-without-starting-completely-from-scratch/" rel="nofollow noreferrer">this blog post</a>, but the issue remains.</p>