IOUtil has:

/**

• Copies the contents from an InputStream to an OutputStream and closes both streams.
• @param input
• @param output
  */
  public static void copyWithClose(InputStream input, OutputStream output)
  {
  try { copy(input, output); }

  finally
  {
  try

  { input.close(); output.close(); }

  catch (final IOException ignore)
  {

}
}
}

Attempt a close on "output" in a separate block. Some logging at trace level on IOExceptions couldn't hurt either.