Problems

Use the following problems to test your programming prowess in functional-style programming in Java. I strongly encourage you to give each problem a try before you turn to the solutions and download the example programs:

1. 178. Working with mapMulti(): Explain and exemplify the JDK 16, mapMulti(). Provide a brief introduction, explain how it works in comparison with flatMap(), and point out when mapMulti() is a good fit.
2. 179. Streaming custom code to map: Imagine a class that shapes some blog posts. Each post is identified by a unique integer id and it has several properties including its tags. The tags of each post are actually represented as a string of tags separated by hashtag (#). Whenever we need the list of tags for a given post, we can call the allTags() helper method. Our goal is to write a stream pipeline that extracts from this list of tags a Map<String, List<Integer>> containing for each tag (key) the list of posts (value).
3. 180. Exemplifying method reference...