Exam 1z0-809 topic 1 question 4 discussion

C (compiled & tested)

C is good

Answer ist C

C is the answer: import java.util.Comparator; import java.util.HashMap; import java.util.Map; import java.util.TreeMap; import java.util.function.IntFunction; import java.util.function.IntUnaryOperator; import java.util.stream.IntStream; class Vehicle { public static void main (String [ ] args) { Map<Integer, String> unsortMap = new HashMap< > ( ); unsortMap.put (10, "z"); unsortMap.put (5, "b"); unsortMap.put (1, "d"); unsortMap.put (7, "e"); unsortMap.put (50, "j"); Map<Integer, String> treeMap = new TreeMap <Integer, String> (new Comparator<Integer> ( ) { @Override public int compare (Integer o1, Integer o2) {return o2.compareTo (o1); } } ); treeMap.putAll (unsortMap); for (Map.Entry<Integer, String> entry : treeMap.entrySet () ) { System.out.print (entry.getValue () + " "); } } }

Answer is C since o2.compareTo(o1) sorts keys in descending order.

C is correct, TreeMap need provide a Comparator, sort is DESC -> C

Correct answer is C because of overriden compare() method which says to compare in DESC order

C (Tested)

C Tested!!

Correct answer is C. Because @Override public int compare (Integer o1, Integer o2) { return o2.compareTo(o1); } is decrease.

Tested

Answer is C (compiled and tested as following): package birdie; import java.util.Comparator; import java.util.HashMap; import java.util.Map; import java.util.TreeMap; import java.util.function.IntFunction; import java.util.function.IntUnaryOperator; import java.util.stream.IntStream; class Vehicle { public static void main (String [ ] args) { Map<Integer, String> unsortMap = new HashMap< > ( ); unsortMap.put (10, "z"); unsortMap.put (5, "b"); unsortMap.put (1, "d"); unsortMap.put (7, "e"); unsortMap.put (50, "j"); Map<Integer, String> treeMap = new TreeMap <Integer, String> (new Comparator<Integer> ( ) { @Override public int compare (Integer o1, Integer o2) {return o2.compareTo (o1); } } ); treeMap.putAll (unsortMap); for (Map.Entry<Integer, String> entry : treeMap.entrySet () ) { System.out.print (entry.getValue () + " "); } } }

import java.util.Comparator; import java.util.HashMap; import java.util.Map; import java.util.TreeMap; public class MyClass { public static void main(String[] args) { //HashMap is an unsorted Map in Java, neither key nor value is sorted. Map<Integer, String> unsortMap = new HashMap<>(); unsortMap.put(10, "z"); unsortMap.put(5, "b"); unsortMap.put(1, "d"); unsortMap.put(7, "e"); unsortMap.put(50, "j"); Map<Integer, String> treeMap = new TreeMap<Integer, String>(new Comparator<Integer>() { @Override public int compare(Integer o1, Integer o2) { //returns values in descending order return o2.compareTo(o1); } }); treeMap.putAll(unsortMap); for (Map.Entry<Integer, String> entry : treeMap.entrySet()) { System.out.print(entry.getValue() + " "); } } } //ANSWER: C. j z e b d

Map<Integer, String> treeMap = new TreeMap <Integer, String> ( (Comparator<? super Integer>) new Comparator<Integer> ( ) { @Override public int compare (Integer o1, Integer o2) { return o2.compareTo(o1); } } ); answer is C

Answer is "j z e b d" .If the compare method is returning o1.compareTo(o2) then the answer is "d b e z j ".