code: private Object invokeMethod(ServletContextImpl appContext, final String methodName, Object[] params) throws Throwable {
  
          try {
              Method method = objectCache.get(methodName);
              if (method == null) {
                  method = appContext.getClass().getMethod(methodName, classCache.get(methodName));
                  objectCache.put(methodName, method);
              }
  
              return executeMethod(method, appContext, params);
          } catch (Exception ex) {
              handleException(ex);
              return null;
          } finally {
              params = null;
          }
      }
docs: Use reflection to invoke the requested method. Cache the method object to speed up the process
  
  @param appContext The AppliationContext object on which the method will be invoked
  @param methodName The method to call.
  @param params The arguments passed to the called method.