title: Java loop through files with the same name in a folder with subfolders
body: <p>I'm writing some Java code to loop through files with the same name in a folder with lots of subfolders, and do some logics on each file:</p>
  
  <pre><code>parentFolder/
              subfolder1/file.txt
              subfolder2/file.txt
              subfolder3/file.txt
              ... ...
              subfolderx/file.txt
  </code></pre>
  
  <p>above is the structure of what does it look like.</p>
  
  <p>How would I do that?</p>