Verbosity

The imperative way of things is pretty verbose. Here is a case in point. The filtering and flattening is pretty long:

import java.util.List;

public class Books {
  private final String author;
  private final List<String> titles;

  public Books(String author, List<String> titles) {
    super();
    this.author = author;
    this.titles = titles;
  }

  public String getAuthor() {
    return author;
  }
  
  public List<String> getTitles() {
    return titles;
  }
}
------------------- PickUpInterestingStuff.java -----------------

import java.util.List;

import com.google.common.collect.Lists;

public class PickUpInterestingStuff {
  public static void main(String[] args) {
    List<Books> listOfBooks = Lists.newArrayList();
    listOfBooks.add(new Books("Carr", Lists.newArrayList("The Mad Hatter Mystery",
      "The Blind Barber")));
    listOfBooks.add(new Books("Christie", Lists.newArrayList("Death On The Nile",
        "Murder in Mesopotamia")));
 ...