Use wildcard in methods returning keys -------------------------------------- Key: ISPN-7108 URL: https://issues.jboss.org/browse/ISPN-7108 Project: Infinispan Issue Type: Enhancement Components: Core Reporter: Radim Vansa Assignee: Radim Vansa Fix For: 9.0.0.Beta1 When a command uses generics (that's the case of functional commands), it stores keys in {{Collection<? extends K>}}. That does not work well with {{getAffectedKeys()}} returning {{Set<Object>}} - besides Collection/Set the generic type also cannot match (because returning {{Set<Object>}} means that you can theoretically insert any {{Object}}). Changing that to wildcard deals with this and makes the collection effectively read-only.