flatMap
Stream.flatMap, as it can be guessed by its name, is the combination of a map and a flatoperation. That means that you first apply a function to your elements, and then flatten it. Stream.maponly applies a function to the stream without flattening the stream.To understand what flattening a stream consists in, consider a structure like [ [1,2,3],[4,5,6],[7,8,9] ] which has "two levels". Flattenin..
2017. 2. 13.