The CustomFailurePolicy interface provides an "init(Cache<K, V> cache)" method, which, according to the JavaDoc, should be invoked during the initialization phase. The method is however never called and my custom XSite failure policy is this never initiated.

It seems that the BackupSenderImpl class initiates the CustomFailurePolicy in its 'start()' method and does not call the 'init(Cache<K,V> cache)' method of the failure policy.