code: private boolean initEventSource() {
          boolean success = false;
          try {
              eventSource = ServerCache.cacheUnit.createEventSource(cacheConfig.useListenerContext, cacheName);
          } catch (Exception ex) {
              com.ibm.ws.ffdc.FFDCFilter.processException(ex, "com.ibm.ws.cache.Cache.initEventSource", "3289", this);
          }
          if (eventSource != null) {
              success = true;
          }
          return success;
      }
docs: This is a helper method to initialize event source for invalidation listener