code: private Templates tryCache(String url) throws Exception {
          Templates x = (Templates) m_cache.get(url);
          if (x == null) {
              synchronized (m_cache) {
                  if (!m_cache.containsKey(url)) {
                      TransformerFactory factory = TransformerFactory.newInstance();
                      if (factory.getClass().getName().equals("net.sf.saxon.TransformerFactoryImpl")) {
                          factory.setAttribute(FeatureKeys.VERSION_WARNING, Boolean.FALSE);
                      }
                      StreamSource ss = new StreamSource(getInputStream(url));
                      ss.setSystemId(url);
                      x = factory.newTemplates(ss);
                      m_cache.put(url, x);
                  }
              }
          }
          return x;
      }
docs: Maintain prepared stylesheets in memory for reuse