code: private File resolveIndexDirectoryPath() throws IOException {
          if (StringUtils.isEmpty(indexDirectoryPath)) {
              indexDirectoryPath = System.getProperty("java.io.tmpdir") + appContext.getApplicationName();
          }
          
          File dir = new File(indexDirectoryPath, getClass().getPackage().getName());
          
          if (!dir.exists() && !dir.mkdirs()) {
              throw new IOException("Failed to create help search index directory.");
          }
          
          log.info("Help search index located at " + dir);
          return dir;
      }
docs: Resolves the index directory path. If a path is not specified, one is created within
  temporary storage.
  
  @return The resolved index directory path.
  @throws IOException Unspecified IO exception.