title: mkdirs() return value for already existing directories
body: <p>File.mkdirs JavaDocs:</p>
  <blockquote>
  <p>public boolean mkdirs()</p>
  <p>Creates the directory named by this abstract pathname, including any necessary but nonexistent parent directories. Note that if this operation fails it may have succeeded in creating some of the necessary parent directories.</p>
  <p>Returns:
  true if and only if the directory was created, along with all necessary parent directories; false otherwise</p>
  </blockquote>
  <p>My question is: Does mkdirs() return false if some of the directories it wanted to create already existed? Or does it just return true if it was successful in creating the entire path for the File, whether or not some directories already existed?</p>