code: @Override
      protected String getCompiledString(final Instance _instance)
      {
          String ret = "";
          try {
              final Checkout checkout = new Checkout(_instance);
              final BufferedReader in = new BufferedReader(new InputStreamReader(checkout.execute(), "UTF-8"));
  
              final CssCompressor compressor = new CssCompressor(in);
              in.close();
              checkout.close();
              final ByteArrayOutputStream byteout = new ByteArrayOutputStream();
              final OutputStreamWriter out = new OutputStreamWriter(byteout, "UTF-8");
              compressor.compress(out, 2000);
              out.flush();
              ret = byteout.toString("UTF-8");
              ret += "\n";
          } catch (final EFapsException e) {
              CSSCompiler.LOG.error("error during checkout of Instance:" + _instance, e);
              e.printStackTrace();
          } catch (final IOException e) {
              CSSCompiler.LOG.error("error during reqding of the Inputstram of Instance with oid:" + _instance, e);
          }
          return ret;
      }
docs: {@inheritDoc}