docs: public String getId() {
          Jenkins h = Jenkins.getInstance();
  
          // in servlet 2.5, we can get the context path
          String contextPath="";
          try {
              Method m = ServletContext.class.getMethod("getContextPath");
              contextPath=" contextPath=\""+m.invoke(h.servletContext)+"\"";
          } catch (Exception e) {
              // maybe running with Servlet 2.4
          }
  
          return h.hashCode()+contextPath+" at "+ManagementFactory.getRuntimeMXBean().getName();
      }