if [[ ! -f ${tmp_pdf_file} ]] ; then
    echo "unoconv does not work."
    exit 1
  fi
  tmp_png_prefix=/tmp/thumbnail.png.$$
  pdftoppm -png -singlefile ${tmp_pdf_file} ${tmp_png_prefix}
  tmp_png_file="${tmp_png_prefix}.png"
  rm -f ${tmp_pdf_file}
  if [[ ! -f ${tmp_png_file} ]] ; then
    echo "pdftoppm does not work."
    exit 1
  fi
  convert -thumbnail ${image_size} ${tmp_png_file} "${output_file}"

#FESS_JAVA_OPTS="$FESS_JAVA_OPTS -Djavax.net.ssl.trustStorePassword=changeit"

# min and max heap sizes should be set to the same value to avoid
# stop-the-world GC pauses during resize, and so that we can lock the
# heap in memory on startup to prevent any of it from being swapped
# out.
FESS_JAVA_OPTS="$FESS_JAVA_OPTS -Xms${FESS_MIN_MEM}"