Java How to Program, Early Objects, 11th Edition

... corresponding Long value is the number of occurrences of that word. The pipeline performs the following tasks:

8

• Line 18 calls Files method lines (added in Java SE 8) which returns a Stream<String> that reads lines of text from a file and returns each line as a String. Class Files (package java.nio.file) is one of many classes throughout the Java APIs which provide methods that return Streams.

8

• Line 19 uses Stream method flatMap to break each line of text into its separate words. Method flatMap receives a Function that maps an object into a stream of elements. In this case, the object is a String containing words and the result is a Stream<String> for the individual words. The lambda in line 19 passes the String representing a line of text to ...