unable to clear last reqirement

Question about the task

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I am unable to clear the last requirement. I know that the values are displaying. I changed the values to be unique from the keys and they output correctly. The code worked properly in the previous lesson for displaying the list of keys.

There is a HashMap<String, String>. 10 different strings have been added to it.
Display a list of values on the screen, each element on a new line.

Requirements:

The program must create a HashMap variable with (String, String) elements. The variable must be initialized immediately.
The program should not read values from the keyboard.
The program should add 10 different strings to the collection in accordance with the conditions.
The printValues() method should display the values in the collection, each element on a new line.

package com.codegym.task.task08.task0805; import java.util.HashMap; import java.util.Map; import java.util.Iterator; /* Values on the screen! */ public class Solution { public static void main(String[] args) throws Exception { HashMap<String, String> map = new HashMap<String, String>(); map.put("Sim", "Sim"); map.put("Tom", "Tom"); map.put("Arbus", "Arbus"); map.put("Baby", "Baby"); map.put("Cat", "Cat"); map.put("Dog", "Dog"); map.put("Eat", "Eat"); map.put("Food", "Food"); map.put("Gevey", "Gevey"); map.put("Hugs", "Hugs"); printValues(map); } public static void printValues(HashMap<String, String> map) { //write your code here Iterator<Map.Entry<String, String>> iterator = map.entrySet().iterator(); while(iterator.hasNext()) { HashMap.Entry<String, String> pair = iterator.next(); String value = pair.getValue(); System.out.println(value); } } }

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Guadalupe Gagnon

Level 37 , Tampa, United States

14 November 2019, 02:28

useful

It looks like you are satisfying the conditions. It may be that you modified the starting code, which is throwing the verification system off. Try changing line 29 back to the original code of:

public static void printValues(Map<String, String> map)

if that doesn't work, copy lines 31 through 38, reset the task, then paste them back in (in the proper location).

ardon polukoff

Level 9 , Lakeland, United States

14 November 2019, 04:32

Thanks Guadalupe! It is working now. Why is the type argument type declared as Map rather than HashMap?

Guadalupe Gagnon

Level 37 , Tampa, United States

14 November 2019, 14:28

solution

Map is an interface that different map classes implement (Hashmap. LinkedHashMap, TreeMap). It is important to know/remember that interfaces can not be instantiated, however variables of interfaces can be declared and initialized to objects that implement the interface. What that means is code like this is illegal:

//↓ creating a variable
Map map = new Map();
       // ↑ initializing an object of an interface type cannot be done

While code like this is perfectly legit:

// ↓ creating a variable
Map map = new HashMap(); // or new LinkedHashmap etc....
       // ↑ initializing an object that implements the Map interface

The verification system most likely uses different types of maps other than just the HashMap for the testing of the code to make sure it works with all map types.