Oracle
1Z0-819 · Question #100
1Z0-819 Question #100: Real Exam Question with Answer & Explanation
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Question
A bookstore's sales are represented by a list of Sale objects populated with the name of the customer and the books they purchased.
public class Sale {
String customer;
private List<Book> items;
/* constructor, setters and getters not shown */
}
public class Book {
private String name;
private double price;
/* constructor, setters and getters not shown */
}
Given a list of Sale objects, lList, which code fragment creates a list of total sales for each customer in ascending order?
Options
- AlList.stream() .collect(groupingBy(Sale::getCustomer, TreeMap::new, summingDouble(sale -> sale.getItems().stream().mapToDouble(Book::getPrice).sum()))); .entrySet().stream().sorted(Map.Entry.comparingByValue()) .collect(mapping(Entry::getKey, toList()));
- BlList.stream() .collect(groupingBy(Sale::getCustomer, summingDouble(sale -> sale.getItems().stream().mapToDouble(Book::getPrice).sum()))); .entrySet().stream().sorted(Map.Entry.comparingByValue()) .collect(mapping(Entry::getKey, toList()));
- ClList.stream() .collect(groupingBy(Sale::getCustomer, summingDouble(sale -> sale.getItems().stream().mapToDouble(Book::getPrice).sum()))); .entrySet().stream().sorted(Map.Entry.comparingByValue()) .collect(mapping(Entry::getKey, toList()));
- DlList.stream() .collect(groupingBy(Sale::getCustomer, summingDouble(sale -> sale.getItems().stream().mapToDouble(Book::getPrice).sum()))); .entrySet().stream().sorted(Map.Entry.comparingByValue()) .collect(mapping(Entry::getKey, toList()));
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