I noticed that, while Stream and its primitive equivalents have multiple map and flapMap methods, Optional and its primitive equivalents were missing those. Since these can still be very useful, I wrote a patch to add the following methods: * Optional: mapToInt, mapToLong, mapToDouble, flatMapToInt, flatMapToLong, flatMapToDouble * OptionalInt: map, mapToObj, mapToLong, mapToDouble, flatMap * OptionalLong: map, mapToObj, mapToInt, mapToDouble, flatMap * OptionalDouble: map, mapToObj, mapToInt, mapToLong, flatMap I did not add any more flatMap methods to OptionalInt, OptionalLong and OptionalDouble because these also don't exist on IntStream, LongStream and DoubleStream. In addition, I also added the missing or method to OptionalInt, OptionalLong and OptionalDouble based on that of Optional. My OCA has been processed on 2019-01-22. Rob