jsonEncodeImpl(sb, val); return sb;
try { jsonEncodeImpl(sb, val); return sb; } catch (Exception e) { env.warning(L.l(e.toString())); log.log(Level.FINE, e.toString(), e); sb.append("null"); return sb; }
  public StringValue json_encode(Env env, Value val)  {    _env = env;    StringBuilderValue sb = new StringBuilderValue();    jsonEncodeImpl(sb, val);    return sb;  }