code: private Method retrieveCustomMethod(final Wave wave) {
          Method customMethod = null;
          // Search the wave handler method to call
          customMethod = this.defaultMethod == null
                  // Method computed according to wave prefix and wave type action
                  // name
                  ? ClassUtility.retrieveMethodList(getWaveReady().getClass(), wave.waveType().toString())
                                .stream()
                                .filter(m -> CheckerUtility.checkMethodSignature(m, wave.waveType().items()))
                                .findFirst().orElse(null)
                  // Method defined with annotation
                  : this.defaultMethod;
  
          if (customMethod == null) {
              LOGGER.info(CUSTOM_METHOD_NOT_FOUND);
          }
          return customMethod;
      }
docs: Retrieve the custom wave handler method.
  
  @param wave the wave to be handled
  
  @return the custom handler method or null if none exists