関連ワード:  java 8 map to list of objects    java stream map to list of objects    java 8 convert map to list of objects    java 8 stream map to list of objects    java stream convert map to list of objects    java 8 create map from list of objects    java stream map list of objects to hashmap    java stream create map from list of objects    java 8 create hashmap from list of objects    java 8 list of objects to map string list of values