Java 8 List into Map

Question

I want to translate a List of objects into a Map using Java 8\'s streams and lambdas.

This is how I would write it in Java 7 and below.

private Map&l         


        

Answer 1

String array[] = {"ASDFASDFASDF","AA", "BBB", "CCCC", "DD", "EEDDDAD"};
    List list = Arrays.asList(array);
    Map map = list.stream()
            .collect(Collectors.toMap(s -> s.length(), s -> s, (x, y) -> {
                System.out.println("Dublicate key" + x);
                return x;
            },()-> new TreeMap<>((s1,s2)->s2.compareTo(s1))));
    System.out.println(map);

Dublicate key AA {12=ASDFASDFASDF, 7=EEDDDAD, 4=CCCC, 3=BBB, 2=AA}