correct, reading a file is inherently
 racy).

 <p>The default implementation of this method in <code>InputStream</code> always returns 0.
 Subclasses should override this method if they are able to indicate the number of bytes
 available.</p></div>
  <div class="jd-tagdata">
      <h5 class="jd-tagtitle">Returns</h5>
      <ul class="nolist"><li>the estimated number of bytes available</li></ul>
  </div>
  <div class="jd-tagdata">
      <h5 class="jd-tagtitle">Throws</h5>
      <table class="jd-tagtable">  