Use Of Flatmap In Java 8

Both of the functions map() and flatmap are used for transformation and mapping operations. Whereas the map () method can extract values from an optional object, it may fail if code design causes the nesting of the optionals. For more on method references (like what does this syntax actually do) make sure you take a look at our guide on method references.

By using the map () function, you can apply any function to every element of the collection. Definition & usage of flatmap () method. On this page we will provide java 8 flatmap example.

Stream.flatmap () returns the stream which will contain the elements obtained by replacement of each element of the source stream by a mapping function and and flattens the result.

Flattening here is of the individual streams from each item in the list to a single stream. Stream.flatmap () returns the stream which will contain the elements obtained by replacement of each element of the source stream by a mapping function and and flattens the result. Map() and flatmap() apis stem from functional languages. The flatmap () does a map + flat.