title: Java Arrays.sort() Taking a Long Time
body: <p>I am using Java's <code>Arrays.sort()</code> function to sort a list of files by their last modified time. The sort for 245 files is taking around 5 seconds. This seems too long to me. I feel it shouldn't take more than 0.5 seconds. Is that a good assumption? What am I doing wrong? OR does this sound normal?</p>
  
  <pre><code>public static class LastModifiedComparator implements Comparator&lt;File&gt; {
      @Override
      public int compare(File f1, File f2) {
          return (int)(f1.lastModified() - f2.lastModified());
      }       
  }
  
  File folder = new File( "C:\\Whatever\\" );
  File[] filesInFolder = folder.listFiles();
  logger.debug("Starting File Sort");
  Arrays.sort(filesInFolder, new LastModifiedComparator());
  logger.debug("Done File Sort");
  </code></pre>
  
  <p>Output in Log</p>
  
  <pre><code>2012-08-10 14:24:20,333 DEBUG http-8080-4 &lt;ClassName&gt;:73 - Starting File Sort
  2012-08-10 14:24:25,915 DEBUG http-8080-4 &lt;ClassName&gt;:75 - Done File Sort
  </code></pre>