title: optimize this java code?
body: <p>I have a quartz scheduler job which scans a directory every 10 seconds and convert all pcl files to pdf files.</p>
  
  <p>Here I put part of the code which scans the directory and loads all the files and for each of it it calls some methods to convert it.</p>
  
  <pre><code>    FileExtensionFilter extFilter = new FileExtensionFilter();
      extFilter.setAllowAll(false);
      extFilter.addExtension(_fExtension);
      // Filter out all files that match.
      File[] filteredFileList = fInbox.listFiles(extFilter);
      for (File fSrc : filteredFileList) {
         try {
            //call the methods to convert fSrc file
         }catch (Exception e){
           //threat exception's code
         }
  </code></pre>
  
  <p>All works nice if I have 30 pcl files but if I have 50 for instance, the processing goes step by step slower. </p>
  
  <p><strong>The question is</strong>: is there any way to improve this loop? Basically to not "wait" for the file to be processed but go further and take another one and so one?</p>
  
  <p>I'm thinking about <em>multithreading</em> but I am not sure if this will work on this filesystem scan conversion task...
  Can you suggest something?</p>
  
  <p>Thanks.</p>
  
  <p>Ps: Please note that If I throw 30 files, and after that another 30 all works great. The performance is affected when I throw <strong>at once</strong> more files...</p>