Java 8 Map And Flatmap

In our last tutorial we looked at map method in java 8 stream example. In java, to convert a 2d array into a 1d array, we can loop the 2d array and put all the elements into a new array; The difference is that the map operation produces one output value for each input value, whereas the flatmap operation produces an arbitrary number (zero or more) values for each input.</p>

Let us start with the examples. There is no flattening in case of map like flatmap. In java, the stream interface has a map() and flatmap() methods and both have intermediate stream operation and return another stream as method output.

3.4 below is the final version, and we combine the array first and follow by a filter later.

Whereas flatmap () method does mapping as well as flattening. Map is intermediate operation provided by stream api which takes function as argument and returns. Java 8 map() and flatmap() operations can be applied to either streams or optional. These two methods map and flatmap can be applied to a stream and they both return a stream only.</p>